Process for beta-lactone production

ABSTRACT

The present application provides a method for producing an beta-lactone product. The method includes the steps of: reacting an epoxide, a solvent with a carbonylation catalyst and carbon monoxide to produce a reaction stream comprising a beta-lactone then separating a portion of the beta-lactone in the reaction stream from the solvent and carbonylation catalyst to produce: i) a beta-lactone stream with the beta-lactone, and ii) a catalyst recycling stream including the carbonylation catalyst and the high boiling solvent; and adding the catalyst recycling stream to the feed stream.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/275,139, filed May 12, 2014 (now U.S. Pat. No. 9,206,144),which is a continuation of U.S. patent application Ser. No. 13/860,179,filed Apr. 10, 2013 (now U.S. Pat. No. 8,796,475), which is acontinuation of U.S. patent application Ser. No. 13/262,985, filed Oct.5, 2011 (now U.S. Pat. No. 8,445,703), which is the National Stageapplication under 35 U.S.C. §371 of International Application No.:PCT/US10/30230, filed Apr. 7, 2010, and claims priority to U.S.Provisional Application Ser. Nos.61/167,711, filed Apr. 8, 2009,61/286,382, filed Dec. 15, 2009, and 61/310,257 filed Mar. 3, 2010, thecontents of each of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

Beta-lactones are useful intermediates in the synthesis of otherchemical compounds including acrylic acid and acrylates. Acrylic acid isused as a precursor in a wide variety of chemical industries. Acrylicacid is typically produced from a feedstock of propene, which is itselfa byproduct of ethylene and gasoline production. Economic andenvironmental circumstances have lead to interest in other methods ofproduction of acrylic acid and other acrylates from a variety offeedstocks. Additional feedstocks can include epoxides.

SUMMARY OF THE INVENTION

In various aspects, the present invention provides a method includingthe steps of reacting the contents of a feed stream including anepoxide, a solvent with a carbonylation catalyst and carbon monoxide toproduce a reaction product stream including a beta-lactone, separating aportion of the beta-lactone in the reaction product stream from thesolvent and carbonylation catalyst to produce: i) a beta-lactone streamwith the beta-lactone, and ii) a catalyst recycling stream including thecarbonylation catalyst; and adding the catalyst recycling stream to thefeed stream.

In some embodiments, the method further includes treating thebeta-lactone stream under conditions to convert the beta lactone into acompound selected from the group consisting of: acrylic acid, methylacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate,2-ethylhexyl acrylate.

In some embodiments, the solvent has a boiling point higher than theboiling point of the beta-lactone, at the same pressure. In someembodiments, the solvent has a boiling point lower than the boilingpoint of the beta-lactone, at the same pressure.

In some embodiments, the beta-lactone stream includes a portion of thesolvent and/or the carbonylation catalyst. In some embodiments, thebeta-lactone stream includes a portion of the epoxide. In someembodiments, the recycling stream comprises beta-lactone. In someembodiments, the reaction product stream comprises a portion of theepoxide.

In some embodiments, the reaction product stream comprises sufficientepoxide to prevent anhydride formation. In some embodiments, thereaction product stream comprises at least about 10% epoxide, at leastabout 5% epoxide, at least about 3% epoxide, or at least about 0.1%epoxide.

In some embodiments, the reaction product stream comprises less thanabout 5% anhydride, or less than about 1% anhydride. In someembodiments, the reaction product stream is essentially free ofanhydride.

In some embodiments, the method further includes treating the catalystrecycling stream, prior to the adding step by performing at least onestep selected from the group consisting of: adding fresh carbonylationcatalyst, removing spent carbonylation catalyst; adding solvent; addingepoxide, adding a portion of the beta-lactone stream; and anycombination of two or more of these.

In some embodiments, the separating step comprises volatilizing aportion of the beta-lactone from the reaction product stream. In someembodiments, the separating step includes exposing the reaction productstream to reduced pressure. In some embodiments, the reduced pressure isbetween about 5 Torr and about 500 Torr. In some embodiments, thereduced pressure is between about 10 Torr and about 100 Torr. In someembodiments, the reduced pressure is sufficient to reduce the boilingpoint of the beta-lactone by about 20 to about 100° C. below its boilingpoint at atmospheric pressure.

In some embodiments, the separating step comprises exposing the reactionproduct stream to elevated temperature. In some embodiments, theelevated temperature is greater than the boiling point of thebeta-lactone but less than the boiling point of the solvent.

In some embodiments, the separating step comprises exposing the reactionproduct stream to reduced pressure and elevated temperature.

In some embodiments, the method further includes a step of condensingthe volatilized beta-lactone from the separating step.

In some embodiments, the method further includes adding a portion of thebeta-lactone stream to the feed stream. In some embodiments, thebeta-lactone stream is added to the feed until the weight percent ofbeta-lactone in the reaction product stream is in the range of about 10%to about 90%, then withdrawing a portion of the beta-lactone stream as aproduct to maintain the weight percent of beta-lactone in the reactionproduct stream in the range of about 10% to about 90%. In someembodiments, the beta-lactone stream is added to the feed until theweight percent of beta-lactone in the reaction product stream is in therange of about 30% to about 65%, then withdrawing a portion of thebeta-lactone stream as a product to maintain the weight percent ofbeta-lactone in the reaction product stream in the range of about 30% toabout 65%. In some embodiments, the beta-lactone stream is added to thefeed until the weight percent of beta-lactone in the reaction productstream is in the range of about 43% to about 53%, then withdrawing aportion of the beta-lactone stream as a product to maintain the weightpercent of beta-lactone in the reaction product stream in the range ofabout 43% to about 53%.

In some embodiments, the method further includes adding a second solventto the beta lactone prior to the step of further treating thebeta-lactone stream under conditions to convert the beta lactone.

In some embodiments, the step of further treating the beta-lactonestream under conditions to convert the beta lactone is performed in thegas phase.

In some embodiments, the boiling point of the solvent is at least 20° C.higher than the boiling point of the beta lactone. In some embodiments,the boiling point of the solvent is between about 20 and about 80° C.higher than the boiling point of the beta-lactone. In some embodiments,the boiling point of the solvent is about 30 to about 60° C. higher thanthe boiling point of the beta lactone.

In some embodiments, the epoxide has the formula

where, R¹ and R², are each independently selected from the groupconsisting of: —H; optionally substituted C₁₋₆ aliphatic; phenyl;optionally substituted C₁₋₆heteroaliphatic; optionally substituted 3- to6-membered carbocycle; and optionally substituted 3- to 6-memberedheterocycle, and where R¹ and R² can optionally be taken together withintervening atoms to form an optionally substituted ring optionallycontaining one or more heteroatoms.

In some embodiments, the epoxide is chosen from the group consisting of:ethylene oxide; propylene oxide; 1,2-butylene oxide; 2,3-butylene oxide;epichlorohydrin; cyclohexene oxide; cyclopentene oxide;3,3,3-Trifluoro-1,2-epoxypropane, styrene oxide; a glycidyl ether; and aglycidyl ester. In some embodiments, the epoxide is ethylene oxide. Insome embodiments, the epoxide is propylene oxide.

In some embodiments, the step of further treating the beta-lactonestream under conditions to convert the beta lactone is performed in thepresence of a compound selected from the group consisting of: analcohol, an amine and a thiol, under conditions that produce thecorresponding acrylic ester, acrylamide, or a thioacrylate respectively.

In some embodiments, the step of further treating the beta-lactonestream under conditions to convert the beta lactone is performed in thepresence of a compound of formula H—Y to afford an acrylate having theformula:

wherein, R¹ and R², are each independently selected from the groupconsisting of: —H, optionally substituted C₁₋₆ aliphatic, optionallysubstituted C₁₋₆ heteroaliphatic, optionally substituted 3- to12-membered carbocycle, and optionally substituted 3- to 12-memberedheterocycle, or R¹ and R² can optionally be taken together withintervening atoms to form an optionally substituted ring optionallycontaining one or more heteroatoms. In some embodiments, Y is selectedfrom the group consisting of OR¹³, NR¹¹R¹², and SR¹³. In someembodiments, R¹¹, R¹², and R¹³ are independently selected from the groupconsisting of: —H; optionally substituted C₁₋₃₂ aliphatic, optionallysubstituted C₁₋₃₂ heteroaliphatic, optionally substituted 3- to14-membered carbocycle, and optionally substituted 3- to 14-memberedheterocycle, or R¹¹ and R¹² can optionally be taken together withintervening atoms to form an optionally substituted ring optionallycontaining one or more heteroatoms.

In some embodiments, the feed stream comprises, ethylene oxide and ahigh boiling solvent that has a boiling point of at least 172° C. atatmospheric pressure; and the reaction product stream containspropiolactone.

In some embodiments, the feed stream comprises propylene oxide and ahigh boiling solvent that has a boiling point of at least 180° C. atatmospheric pressure; and the reaction product stream containspropiolactone.

In some embodiments, wherein the solvent is selected from the groupconsisting of: sulfolane; N-methyl pyrrolidone;1,3-Dimethyl-2-imidazolidinone diglyme; triglyme; tetraglyme; ethylenecarbonate; propylene carbonate; dibasic esters; THF, THF modified with aC₁₋₃₂ aliphatic; and mixtures of any two or more of these. In someembodiments, the solvent is THF. In some embodiments, the solvent issulfolane. In some embodiments, the solvent is a dibasic ester. In someembodiments, the solvent is a mixture of sulfolane and THF. In someembodiments, the solvent is a mixture of sulfolane and THF modified witha C₁₋₃₂ aliphatic. In some embodiments, the solvent further comprisesdimethyl ether isosorbide.

In some embodiments, the modified THF has the form:

wherein, R is an aliphatic, aromatic, ether, or ester group any of whichcontains more than four carbon atoms.

In some embodiments, the carbonylation catalyst comprises a metalcarbonyl compound.

In some embodiments, the metal carbonyl compound has the general formula[QM_(y)(CO)_(w)]^(x), where: Q is any ligand and need not be present; Mis a metal atom; y is an integer from 1 to 6 inclusive; w is a numbersuch as to provide the stable metal carbonyl; and x is an integer from−3 to +3 inclusive.

In some embodiments, M is selected from the group consisting of Ti, Cr,Mn, Fe, Ru, Co, Rh, Ni, Pd, Cu, Zn, Al, Ga and In. In some embodiments,wherein M is Co. In some embodiments, M is Co, y is 1, and w is 4.

In some embodiments, the carbonylation catalyst further comprises aLewis acidic co-catalyst.

In some embodiments, the metal carbonyl compound is anionic, and theLewis acidic co-catalyst is cationic. In some embodiments, the metalcarbonyl complex comprises a carbonyl cobaltate and the Lewis acidicco-catalyst comprises a metal-centered cationic Lewis acid.

In some embodiments, the metal-centered cationic Lewis acid is a metalcomplex of formula [M′(L)_(b)]^(c+), where, M′ is a metal; each L is aligand; b is an integer from 1 to 6 inclusive; c is 1, 2, or 3; andwhere, if more than one L is present, each L may be the same ordifferent.

In some embodiments, is selected from the group consisting of: atransition metal, a group 13 or 14 metal, and a lanthanide. In someembodiments, M′ is a transition metal or a group 13 metal. In someembodiments, M′ is selected from the group consisting of aluminum,chromium, indium and gallium. In some embodiments, M′ is aluminum. Insome embodiments, M′ is chromium.

In some embodiments, the Lewis acid includes a dianionic tetradentateligand. In some embodiments, the dianionic tetradentate ligand isselected from the group consisting of: porphyrin derivatives; salenderivatives; dibenzotetramethyltetraaza[14]annulene (“TMTAA”)derivatives; phthalocyaninate derivatives; and derivatives of the Trostligand.

In some embodiments, the treating step is mediated by a catalyst. Insome embodiments, the catalyst in the treating step is an acid catalyst.In some embodiments, the catalyst in the treating step is a basiccatalyst.

In some embodiments, the reacting step is performed in adiabaticreactor. In some embodiments, the adiabatic reactor is a tubularreactor. In some embodiments, the adiabatic reactor is a shell and tubereactor.

In some embodiments, the reacting step is performed at a pressure fromabout 50 psi to about 5000 psi. In some embodiments, the reacting stepis performed at a pressure from about 50 psi to about 1500 psi. In someembodiments, the reacting step is performed at a pressure from about 200psi to about 800 psi. In some embodiments, the reacting step isperformed at a pressure of about 400 psi.

In some embodiments, the reacting step is performed at a temperaturefrom about 0° C. to about 125° C.

In some embodiments, the reacting step is performed at a temperaturefrom about 30° C. to about 100° C. In some embodiments, the reactingstep is performed at a temperature from about 40° C. to about 80° C.

In some embodiments, the carbon monoxide in the reacting step issupplied as an industrial gas stream comprising carbon monoxide and oneor more additional gases. In some embodiments, the industrial gas streamcomprises syngas. In some embodiments, the carbon monoxide in thereacting step is supplied in substantially pure form.

In some embodiments, the beta-lactone stream comprises residualunreacted epoxide, carbon monoxide, or solvent. In some embodiments, theepoxide, carbon monoxide or solvent are returned to the feed stream. Insome embodiments, a portion of the beta-lactone stream is returned tothe feed.

In various aspects the present invention provides a method includingsteps of reacting the contents of a feed stream comprising an epoxide, asolvent, a carbonylation catalyst and carbon monoxide to produce areaction product stream comprising a beta-lactone; separating at least aportion of the beta-lactone in the reaction product stream from thesolvent and carbonylation catalyst to produce: i) a beta-lactone streamcomprising the beta-lactone, and ii) a catalyst recycling streamcomprising the carbonylation catalyst; and adding the catalyst recyclingstream to the feed stream.

In some embodiments, the separating step includes steps of a firstseparating step to separate the reaction product stream into i) agaseous stream comprising carbon monoxide, and the epoxide; and ii) aliquid stream comprising the beta-lactone, and the carbonylationcatalyst; and a second separating step to separate at least a portion ofthe beta-lactone in the liquid stream from the solvent and carbonylationcatalyst to produce: i) a beta-lactone stream comprising thebeta-lactone; and ii) the catalyst recycling stream comprising thecarbonylation catalyst.

In some embodiments, the first separating step includes steps ofseparating the reaction product stream into i) a gaseous streamcomprising carbon monoxide and a portion of the epoxide, and ii) aliquid stream comprising a remainder of the epoxide, the beta-lactone,and the carbonylation catalyst; and separating the liquid stream into i)an epoxide stream comprising the remainder of the epoxide; and ii) thenonvolatile stream comprising the beta-lactone, and the carbonylationcatalyst.

In some embodiments, the catalyst recycling stream further includes atleast a portion of the solvent, where the solvent has a boiling pointhigher than the boiling point of the beta-lactone. In some embodiments,the method includes the step of returning the gaseous stream to the feedstream. In some embodiments, the method includes the step of returningthe beta-lactone stream to the feed stream. In some embodiments, themethod includes the step of returning the catalyst recycling stream tothe feed stream.

In some embodiments, the gaseous stream further includes a portion ofthe solvent, where the solvent has a boiling point lower than theboiling point of the beta-lactone. In some embodiments, the gaseousstream is returned to the feed stream. In some embodiments, the methodincludes the step of returning at least one of the gaseous stream andthe epoxide stream to the feed stream. In some embodiments, the methodincludes the step of returning the liquid stream to the feed stream. Insome embodiments, the method includes the step of returning thenonvolatile stream to the feed stream. In some embodiments, the epoxidestream further comprises a portion of the solvent, where the solvent hasthe boiling point lower than the boiling point of the beta-lactone. Insome embodiments, the gaseous stream is returned to the feed stream.

In some embodiments, the feed stream further comprises a Lewis baseadditive. In some embodiments, the Lewis base additive is selected frommodified THF; 2,6-lutidine; imidazole; 1-methylimidazole4-dimethylaminopyridine; trihexylamine, and triphenylphosphine.

In various aspects, the invention includes a method including steps of:reacting the contents of a feed stream comprising an epoxide, a solventwith a carbonylation catalyst and carbon monoxide to produce a reactionproduct stream comprising a beta-lactone; returning the entirety of thereaction product stream to the feed stream until the weight percent ofbeta-lactone in the reaction product stream is in a predetermined range;then separating at least a portion of the beta-lactone in the reactionproduct stream from the solvent and carbonylation catalyst to produce:i) a beta-lactone stream comprising the beta-lactone, and ii) a catalystrecycling stream comprising the carbonylation catalyst and the solvent;and adding the catalyst recycling stream to the feed stream.

In some embodiments, the reaction product stream is returned to the feeduntil the weight percent of beta-lactone in the reaction product streamis in the range of about 10% to about 90%, then withdrawing a portion ofthe beta-lactone stream as a product to maintain the weight percent ofbeta-lactone in the reaction product stream in the range of about 10% toabout 90%, is in the range of about 30% to about 65%, or in the range ofabout 43% to about 53%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a process flow diagram of exemplary reaction system.

FIG. 2 shows a flow chart of exemplary reaction and process steps.

FIG. 3 is a graph of absorbance of propriolactone (1823 cm-1), ethyleneoxide (867 cm-1), and acetaldehyde (1724 cm-1) monitored during thecarbonylation reaction in sulfolane, with a starting concentration ofethylene oxide of 1.0 M.

FIG. 4 is a graph of absorbance of propriolactone (1823 cm-1), ethyleneoxide (867 cm-1), and acetaldehyde (1724 cm-1) monitored during thecarbonylation reaction in sulfolane with a starting concentration ofethylene oxide of 1.8 M.

FIG. 5 is a graph of absorbance of propriolactone (1823 cm-1), ethyleneoxide (867 cm-1), and acetaldehyde (1724 cm-1) monitored during thecarbonylation reaction in dibasic ester.

FIG. 6 is a graph of absorbance of propriolactone (1823 cm-1), ethyleneoxide (867 cm-1), and SA (1791 cm-1) monitored during the carbonylationreaction in sulfolane with additional propriolactone and ethylene oxideadded during the reaction.

FIG. 7 is a graph of showing the formation of propriolactone during thefirst 5 min of the ethylene oxide carbonylation for variousconcentrations of propriolactone recycle.

FIG. 8 is a graph of propriolactone concentration for a reaction runwith a second catalyst injection at 13.8% percent propriolactone.

FIG. 9 is a graph of concentration of propylene oxide, propiolactone andacetone for a series of carbonylation reactions at 200 psi in 1,4Dioxane at 90° C.

FIG. 10 is a graph of concentration of propylene oxide, propiolactoneand acetone for a series of carbonylation reactions at 200 psi in 1,4Dioxane at 30° C.

FIG. 11 is a graph of the concentrations of propylene oxide (“PO”),b-butyrolactone and methylsuccinic anhydride during the carbonylation ofPO in DBE-3. Reaction conditions: Parr reactor, [PO]=1.8 M,[PO]:[cat]=500, 60° C. (up to 77° C.), 400 psi CO.

FIG. 12 is a graph of the concentrations of propylene oxide (“PO”),beta-butyrolactone and methylsuccinic anhydride during the carbonylationof PO in DBE-3. Reaction conditions: Parr reactor, [PO]=1.8 M,[PO]:[cat]=500, 60° C., 400 psi CO. A second PO injection was performedat 100 min.

FIG. 13 is graph of the concentration of beta-butyrolactone in a seriesof carbonylation reactions of PO in THF. Reaction conditions: Parrreactor, [PO]=1.8 M, 55° C. with varying catalyst to oxide ratios.

FIG. 14 is a graph of the concentrations of propylene oxide (“PO”) andbeta-butyrolactone (“BBL”) during a carbonylation of PO in THF. Reactionconditions: Parr reactor, [PO]=1.8 M, [PO]:[cat]=1500, 55° C., 200 psiCO. Additional PO injections were performed at 3 h and 20 h.

FIG. 15 is a graph of the concentrations of propylene oxide (“PO”),beta-butyrolactone during a series of carbonylation reactions withvarying amounts of beta-lactone recycling. Reaction conditions: Parrreactor, [PO]=1.8 M, [PO]:[cat]=250, 60° C., 400 psi, sulfolane. Productwas distilled from the reaction mixture at 90° C. under full vacuumafter the first cycle.

FIG. 16 shows an 1H NMR spectrum (400 MHz, DMSO-d6) of[(Cl-TPP)Al][Co(CO )4].

FIG. 17 shows the infrared spectra of (Cl-TPP)AlCl, NaCo(CO)4, and[(Cl-TPP)Al][Co(CO)4].

FIG. 18 is a graph of the infrared spectra of reaction solution in thecarbonylation of propylene oxide in DBE-3 ([Co]=15 mM, [PO]=2.86 M,[PO]:[Co]=200, 30° C., 400 psi CO)

FIG. 19 is a graph of the infrared spectra of reaction solution in thecarbonylation of ethylene oxide in sulfolane at various reaction times([Co]=3.6 mM, [EO]=1.8 M, [EO]:[Co]=500, 80° C., 400 psi CO)

FIG. 20 shows infrared absorbance during reaction progress monitoring byin situ IR in the reaction of ethylene oxide in sulfolane ([Co]=3.6 mM,[EO]=1.8 M, [EO]:[Co]=500, 65° C.).

FIG. 21 shows initial rates monitored by in situ IR in the reaction ofethylene oxide in THF and sulfolane ([Co]=3.6 mM, [EO]=1.8 M, 600 psiCO).

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

The present invention encompasses methods for the-continuous productionof beta-lactone from an epoxide feedstock. In various aspects, theinvention encompasses methods of carbonylation 1 of epoxide compounds(e.g., ethylene oxide) to yield a beta-lactone (e.g.,beta-propiolactone) in a reaction product stream 200. The beta-lactoneis further separated 2 or isolated from the other components of thereaction product stream. The beta-lactone is further transformed to anacrylate (e.g., acrylic acid) 3. In some embodiments, the carbonylationreaction 1 is in the presence a catalyst. In some embodiments, theepoxide is reacted with carbon monoxide. In some embodiments, thecatalyst is present in a solvent. Scheme 1 below illustrates thereaction sequence in one embodiment of the invention.

Definitions

Definitions of specific functional groups and chemical terms aredescribed in more detail below. For purposes of this invention, thechemical elements are identified in accordance with the Periodic Tableof the Elements, CAS version, Handbook of Chemistry and Physics, 75^(th)Ed., inside cover, and specific functional groups are generally definedas described therein. Additionally, general principles of organicchemistry, as well as specific functional moieties and reactivity, aredescribed in Organic Chemistry, Thomas Sorrell, University ScienceBooks, Sausalito, 1999; Smith and March March's Advanced OrganicChemistry, 5^(th) Edition, John Wiley & Sons, Inc., New York, 2001;Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., NewYork, 1989; Carruthers, Some Modern Methods of Organic Synthesis, 3^(rd)Edition, Cambridge University Press, Cambridge, 1987; the entirecontents of each of which are incorporated herein by reference.

Certain compounds, as described herein may have one or more double bondsthat can exist as either a Z or E isomer, unless otherwise indicated.The invention additionally encompasses the compounds as individualisomers substantially free of other isomers and alternatively, asmixtures of various isomers, e.g., racemic mixtures of enantiomers. Inaddition to the above-mentioned compounds per se, this invention alsoencompasses compositions comprising one or more compounds.

As used herein, the term “isomers” includes any and all geometricisomers and stereoisomers. For example, “isomers” include cis- andtrans-isomers, E- and Z-isomers, R- and S-enantiomers, diastereomers,(D)-isomers, (L)-isomers, racemic mixtures thereof, and other mixturesthereof, as falling within the scope of the invention. For instance, acompound may, in some embodiments, be provided substantially free of oneor more corresponding stereoisomers, and may also be referred to as“stereochemically enriched.”

The terms “halo” and “halogen” as used herein refer to an atom selectedfrom fluorine (fluoro, —F), chlorine (chloro, —Cl), bromine (bromo,—Br), and iodine (iodo, —I). The term “halogenic” as used herein refersto a compound substituted with one or more halogen atoms.

The term “aliphatic” or “aliphatic group”, as used herein, denotes ahydrocarbon moiety that may be straight-chain (i.e., unbranched),branched, or cyclic (including fused, bridging, and spiro-fusedpolycyclic) and may be completely saturated or may contain one or moreunits of unsaturation, but which is not aromatic. Unless otherwisespecified, aliphatic groups contain 1-30 carbon atoms. In certainembodiments, aliphatic groups contain 1-12 carbon atoms. In certainembodiments, aliphatic groups contain 1-8 carbon atoms. In certainembodiments, aliphatic groups contain 1-6 carbon atoms. In someembodiments, aliphatic groups contain 1-5 carbon atoms, in someembodiments, aliphatic groups contain 1-4 carbon atoms, in yet otherembodiments aliphatic groups contain 1-3 carbon atoms, and in yet otherembodiments aliphatic groups contain 1-2 carbon atoms. Suitablealiphatic groups include, but are not limited to, linear or branched,alkyl, alkenyl, and alkynyl groups, and hybrids thereof such as(cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

The term “heteroaliphatic,” as used herein, refers to aliphatic groupswherein one or more carbon atoms are independently replaced by one ormore atoms selected from the group consisting of oxygen, sulfur,nitrogen, phosphorus, or boron. In certain embodiments, one or twocarbon atoms are independently replaced by one or more of oxygen,sulfur, nitrogen, or phosphorus. Heteroaliphatic groups may besubstituted or unsubstituted, branched or unbranched, cyclic or acyclic,and include “heterocycle,” “heterocyclyl,” “heterocycloaliphatic,” or“heterocyclic” groups.

The term “epoxide”, as used herein, refers to a substituted orunsubstituted oxirane. Substituted oxiranes include monosubstitutedoxiranes, disubstituted oxiranes, trisubstituted oxiranes, andtetrasubstituted oxiranes. Such epoxides may be further optionallysubstituted as defined herein. In certain embodiments, epoxides comprisea single oxirane moiety. In certain embodiments, epoxides comprise twoor more oxirane moieties.

The term “acrylate” or “acrylates” as used herein refer to any acylgroup having a vinyl group adjacent to the acyl carbonyl. The termsencompass mono-, di- and tri-substituted vinyl groups. Examples ofacrylates include, but are not limited to: acrylate, methacrylate,ethacrylate, cinnamate (3-phenylacrylate), crotonate, tiglate, andsenecioate. Because it is known that cylcopropane groups can in certaininstances behave very much like double bonds, cyclopropane esters arespecifically included within the definition of acrylate herein.

The term “polymer”, as used herein, refers to a molecule of highrelative molecular mass, the structure of which comprises the multiplerepetition of units derived, actually or conceptually, from molecules oflow relative molecular mass. In certain embodiments, a polymer iscomprised of only one monomer species (e.g., polyethylene oxide). Incertain embodiments, a polymer of the present invention is a copolymer,terpolymer, heteropolymer, block copolymer, or tapered heteropolymer ofone or more epoxides.

The term “unsaturated”, as used herein, means that a moiety has one ormore double or triple bonds.

The term “alkyl,” as used herein, refers to saturated, straight- orbranched-chain hydrocarbon radicals derived from an aliphatic moietycontaining between one and six carbon atoms by removal of a singlehydrogen atom. Unless otherwise specified, alkyl groups contain 1-12carbon atoms. In certain embodiments, alkyl groups contain 1-8 carbonatoms. In certain embodiments, alkyl groups contain 1-6 carbon atoms. Insome embodiments, alkyl groups contain 1-5 carbon atoms, in someembodiments, alkyl groups contain 1-4 carbon atoms, in yet otherembodiments alkyl groups contain 1-3 carbon atoms, and in yet otherembodiments alkyl groups contain 1-2 carbon atoms. Examples of alkylradicals include, but are not limited to, methyl, ethyl, n-propyl,isopropyl, n-butyl, iso-butyl, sec-butyl, sec-pentyl, iso-pentyl,tert-butyl, n-pentyl, neopentyl, n-hexyl, sec-hexyl, n-heptyl, n-octyl,n-decyl, n-undecyl, dodecyl, and the like.

The term “carbocycle” and “carbocyclic ring” as used herein, refers tomonocyclic and polycyclic moieties wherein the rings contain only carbonatoms. Unless otherwise specified, carbocycles may be saturated,partially unsaturated or aromatic, and contain 3 to 20 carbon atoms. Theterms “carbocycle” or “carbocyclic” also include aliphatic rings thatare fused to one or more aromatic or nonaromatic rings, such asdecahydronaphthyl or tetrahydronaphthyl, where the radical or point ofattachment is on the aliphatic ring. In some embodiments, a carbocyclicgroups is bicyclic. In some embodiments, a carbocyclic group istricyclic. In some embodiments, a carbocyclic group is polycyclic. Incertain embodiments, the terms “3- to 14-membered carbocycle” and “C₃₋₁₄carbocycle” refer to a 3- to 8-membered saturated or partiallyunsaturated monocyclic carbocyclic ring, or a 7- to 14-memberedsaturated or partially unsaturated polycyclic carbocyclic ring.

Representative carbocyles include cyclopropane, cyclobutane,cyclopentane, cyclohexane, bicyclo[2,2,1]heptane, norbornene, phenyl,cyclohexene, naphthalene, spiro[4.5]decane,

The term “aryl” used alone or as part of a larger moiety as in“aralkyl”, “aralkoxy”, or “aryloxyalkyl”, refers to monocyclic andpolycyclic ring systems having a total of five to 20 ring members,wherein at least one ring in the system is aromatic and wherein eachring in the system contains three to twelve ring members. The term“aryl” may be used interchangeably with the term “aryl ring”. In certainembodiments of the present invention, “aryl” refers to an aromatic ringsystem which includes, but is not limited to, phenyl, biphenyl,naphthyl, anthracyl and the like, which may bear one or moresubstituents. Also included within the scope of the term “aryl”, as itis used herein, is a group in which an aromatic ring is fused to one ormore additional rings, such as benzofuranyl, indanyl, phthalimidyl,naphthimidyl, phenantriidinyl, or tetrahydronaphthyl, and the like. Incertain embodiments, the terms “6- to 10-membered aryl” and “C₆₋₁₀ aryl”refer to a phenyl or an 8- to 10-membered polycyclic aryl ring.

The terms “heteroaryl” and “heteroar-”, used alone or as part of alarger moiety, e.g., “heteroaralkyl”, or “heteroaralkoxy”, refer togroups having 5 to 14 ring atoms, preferably 5, 6, or 9 ring atoms;having 6, 10, or 14 electrons shared in a cyclic array; and having, inaddition to carbon atoms, from one to five heteroatoms. The term“heteroatom” refers to nitrogen, oxygen, or sulfur, and includes anyoxidized form of nitrogen or sulfur, and any quaternized form of a basicnitrogen. Heteroaryl groups include, without limitation, thienyl,furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl,oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl,thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl,purinyl, naphthyridinyl, benzofuranyl and pteridinyl. The terms“heteroaryl” and “heteroar-”, as used herein, also include groups inwhich a heteroaromatic ring is fused to one or more aryl,cycloaliphatic, or heterocyclyl rings, where the radical or point ofattachment is on the heteroaromatic ring. Nonlimiting examples includeindolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl,indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl,cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 4H-quinolizinyl,carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl,tetrahydroquinolinyl, tetrahydroisoquinolinyl, andpyrido[2,3-b]-1,4-oxazin-3(4H)-one. A heteroaryl group may be mono- orbicyclic. The term “heteroaryl” may be used interchangeably with theterms “heteroaryl ring”, “heteroaryl group”, or “heteroaromatic”, any ofwhich terms include rings that are optionally substituted. The term“heteroaralkyl” refers to an alkyl group substituted by a heteroaryl,wherein the alkyl and heteroaryl portions independently are optionallysubstituted. In certain embodiments, the term “5- to 14-memberedheteroaryl” refers to a 5- to 6-membered heteroaryl ring having 1 to 3heteroatoms independently selected from nitrogen, oxygen, or sulfur, oran 8- to 14-membered polycyclic heteroaryl ring having 1 to 4heteroatoms independently selected from nitrogen, oxygen, or sulfur.

As used herein, the terms “heterocycle”, “heterocyclyl”, “heterocyclicradical”, and “heterocyclic ring” are used interchangeably and refer toa stable 5- to 7-membered monocyclic or 7-14-membered bicyclicheterocyclic moiety that is either saturated, partially unsaturated, oraromatic and having, in addition to carbon atoms, one or more,preferably one to four, heteroatoms, as defined above. When used inreference to a ring atom of a heterocycle, the term “nitrogen” includesa substituted nitrogen. As an example, in a saturated or partiallyunsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur ornitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (asin pyrrolidinyl), or ⁺NR (as in N-substituted pyrrolidinyl). In someembodiments, the term “3- to 14-membered heterocycle” refers to a 3- to8-membered saturated or partially unsaturated monocyclic heterocyclicring having 1 to 2 heteroatoms independently selected from nitrogen,oxygen, or sulfur, or a 7- to 14-membered saturated or partiallyunsaturated polycyclic heterocyclic ring having 1-3 heteroatomsindependently selected from nitrogen, oxygen, or sulfur.

A heterocyclic ring can be attached to its pendant group at anyheteroatom or carbon atom that results in a stable structure and any ofthe ring atoms can be optionally substituted. Examples of such saturatedor partially unsaturated heterocyclic radicals include, withoutlimitation, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl,pyrrolidonyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl,tetrahydroisoquinolinyl, decahydroquinolinyl, oxazolidinyl, piperazinyl,dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl,and quinuclidinyl. The terms “heterocycle”, “heterocyclyl”,“heterocyclyl ring”, “heterocyclic group”, “heterocyclic moiety”, and“heterocyclic radical”, are used interchangeably herein, and alsoinclude groups in which a heterocyclyl ring is fused to one or morearyl, heteroaryl, or cycloaliphatic rings, such as indolinyl,3H-indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl, wherethe radical or point of attachment is on the heterocyclyl ring. Aheterocyclyl group may be mono- or bicyclic. The term“heterocyclylalkyl” refers to an alkyl group substituted by aheterocyclyl, wherein the alkyl and heterocyclyl portions independentlyare optionally substituted.

As used herein, the term “partially unsaturated” refers to a ring moietythat includes at least one double or triple bond. The term “partiallyunsaturated” is intended to encompass rings having multiple sites ofunsaturation, but is not intended to include aryl or heteroarylmoieties, as herein defined.

As described herein, compounds of the invention may contain “optionallysubstituted” moieties. In general, the term “substituted”, whetherpreceded by the term “optionally” or not, means that one or morehydrogens of the designated moiety are replaced with a suitablesubstituent. Unless otherwise indicated, an “optionally substituted”group may have a suitable substituent at each substitutable position ofthe group, and when more than one position in any given structure may besubstituted with more than one substituent selected from a specifiedgroup, the substituent may be either the same or different at everyposition. Combinations of substituents envisioned by this invention arepreferably those that result in the formation of stable or chemicallyfeasible compounds. The term “stable”, as used herein, refers tocompounds that are not substantially altered when subjected toconditions to allow for their production, detection, and, in certainembodiments, their recovery, purification, and use for one or more ofthe purposes disclosed herein.

Suitable monovalent substituents on a substitutable carbon atom of an“optionally substituted” group are independently halogen;—(CH₂)₀₋₄R^(∘); —(CH₂)₀₋₄OR^(∘); —O—(CH₂)₀₋₄C(O)OR^(∘);—(CH₂)₀₋₄CH(OR^(∘))₂; —(CH₂)₀₋₄SR^(∘); —(CH₂)₀₋₄Ph, which may besubstituted with R^(∘); —(CH₂)₀₋₄O(CH₂)₀₋₁Ph which may be substitutedwith R^(∘); —CH═CHPh, which may be substituted with R^(∘); —NO₂; —CN;—N₃; —(CH₂)₀₋₄N(R^(∘))₂; —(CH₂)₀₋₄N(R^(∘))C(O)R^(∘); —N(R^(∘))C(S)R^(∘);—(CH₂)₀₋₄N(R^(∘))C(O)NR^(∘) ₂; —N(R^(∘))C(S)NR^(∘) ₂;—(CH₂)₀₋₄N(R^(∘))C(O)OR^(∘); —N(R^(∘))N(R^(∘))C(O)R^(∘);—N(R^(∘))N(R^(∘))C(O)NR^(∘) ₂; —N(R^(∘))N(R^(∘))C(O)OR^(∘);—(CH₂)₀₋₄C(O)R^(∘); —C(S)R^(∘); —(CH₂)₀₋₄C(O)OR^(∘);—(CH₂)₀₋₄C(O)N(R^(∘))₂; —(CH₂)₀₋₄C(O)SR^(∘); —(CH₂)₀₋₄C(O)OSiR^(∘) ₃;—(CH₂)₀₋₄OC(O)R^(∘); —OC(O)(CH₂)₀₋₄SR—, SC(S)SR^(∘);—(CH₂)₀₋₄SC(O)R^(∘); —(CH₂)₀₋₄C(O)NR^(∘) ₂; —C(S)NR^(∘) ₂; —C(S)SR^(∘);—SC(S)SR^(∘), —(CH₂)₀₋₄OC(O)NR^(∘) ₂; —C(O)N(OR^(∘))R^(∘);—C(O)C(O)R^(∘); —C(O)CH₂C(O)R^(∘); —C(NOR^(∘))R^(∘); —(CH₂)₀₋₄SSR^(∘);—(CH₂)₀₋₄S(O)₂R^(∘); —(CH₂)₀₋₄S(O)₂OR^(∘); —(CH₂)₀₋₄OS(O)₂R^(∘);—S(O)₂NR^(∘) ₂; —(CH₂)₀₋₄S(O)R^(∘); —N(R^(∘))S(O)₂NR^(∘) ₂;—N(R^(∘))S(O)₂R^(∘); —N(OR^(∘))R^(∘); —C(NH)NR^(∘) ₂; —P(O)₂R^(∘);—P(O)R^(∘) ₂; —OP(O)R^(∘) ₂; —OP(O)(OR^(∘))₂; SiR^(∘) ₃; —(C₁₋₄ straightor branched)alkylene)O—N(R^(∘))₂; or —(C₁₋₄ straight orbranched)alkylene)C(O)O—N(R^(∘))₂, wherein each R^(∘)may be substitutedas defined below and is independently hydrogen, C₁₋₈ aliphatic, —CH₂Ph,—O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur, or, notwithstanding the definition above, twoindependent occurrences of R^(∘), taken together with their interveningatom(s), form a 3-12-membered saturated, partially unsaturated, or arylmono- or polycyclic ring having 0-4 heteroatoms independently selectedfrom nitrogen, oxygen, or sulfur, which may be substituted as definedbelow.

Suitable monovalent substituents on R^(∘) (or the ring formed by takingtwo independent occurrences of R° together with their interveningatoms), are independently halogen, —(CH₂)₀₋₂R^(●), -(haloR^(●)),—(CH₂)₀₋₂OH, —(CH₂)₀₋₂OR^(●), —(CH₂)₀₋₂CH(OR^(●))₂; —O(haloR^(●)), —CN,—N₃, —(CH₂)₀₋₂C(O)R^(●), —(CH₂)₀₋₂C(O)OH, —(CH₂)₀₋₂C(O)OR^(●),—(CH₂)₀₋₄C(O)N(R^(∘))₂; —(CH₂)₀₋₂SR^(●), —(CH₂)₀₋₂SH, —(CH₂)₀₋₂NH₂,—(CH₂)₀₋₂NHR^(●), —(CH₂)₀₋₂NR^(●) ₂, —NO₂, —SiR^(●) ₃, —OSiR^(●) ₃,—C(O)SR^(●), —(C₁₋₄ straight or branched alkylene)C(O)OR^(●), or—SSR^(●) wherein each R^(●) is unsubstituted or where preceded by “halo”is substituted only with one or more halogens, and is independentlyselected from C₁₋₄ aliphatic, —CH₂Ph, —O(CH₂)₀₋₁Ph, or a 5-6-memberedsaturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur. Suitabledivalent substituents on a saturated carbon atom of R° include ═O and═S.

Suitable divalent substituents on a saturated carbon atom of an“optionally substituted” group include the following: ═O, ═S, ═NNR*₂,═NNHC(O)R*, ═NNHC(O)OR*, ═NNHS(O)₂R*, ═NR*, ═NOR*, —O(C(R*₂))₂₋₃O—, or—S(C(R*₂))₂₋₃S—, wherein each independent occurrence of R* is selectedfrom hydrogen, C₁₋₆ aliphatic which may be substituted as defined below,or an unsubstituted 5-6-membered saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur. Suitable divalent substituents that are bound tovicinal substitutable carbons of an “optionally substituted” groupinclude: —O(CR*₂)₂₋₃O—, wherein each independent occurrence of R* isselected from hydrogen, C₁₋₆ aliphatic which may be substituted asdefined below, or an unsubstituted 5-6-membered saturated, partiallyunsaturated, or aryl ring having 0-4 heteroatoms independently selectedfrom nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of R* include halogen,—R^(●), -(haloR^(●)), —OH, —OR^(●), —O(haloR^(●)), —CN, —C(O)OH,—C(O)OR^(●), —NH₂, —NHR^(●), —NR^(●) ₂, or —NO₂, wherein each R^(●) isunsubstituted or where preceded by “halo” is substituted only with oneor more halogens, and is independently C₁₋₄ aliphatic, —CH₂Ph,—O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur.

Suitable substituents on a substitutable nitrogen of an “optionallysubstituted” group include —R^(†), —NR^(†) ₂, —C(O)R^(†), —C(O)OR^(†),—C(O)C(O)R^(†), —C(O)CH₂C(O)R^(†), —S(O)₂R^(†), —S(O)₂NR^(†) ₂,—C(S)NR^(†) ₂, —C(NH)NR^(†) ₂, or —N(R^(†))S(O)₂R^(†); wherein eachR^(†) is independently hydrogen, C₁₋₆ aliphatic which may be substitutedas defined below, unsubstituted —OPh, or an unsubstituted 5-6-memberedsaturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, or,notwithstanding the definition above, two independent occurrences ofR^(†), taken together with their intervening atom(s) form anunsubstituted 3-12-membered saturated, partially unsaturated, or arylmono- or bicyclic ring having 0-4 heteroatoms independently selectedfrom nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of Rt are independentlyhalogen, —R^(●), —(haloR^(●)), —OH, —OR^(●), —O(haloR^(●)), —CN,—C(O)OH, —C(O)OR^(●), —NH₂, —NHR^(●), —NR^(●) ₂, or —NO₂, wherein eachR^(●) is unsubstituted or where preceded by “halo” is substituted onlywith one or more halogens, and is independently C₁₋₄ aliphatic, —CH₂Ph,—O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur.

As used herein, the term “catalyst” refers to a substance the presenceof which increases the rate of a chemical reaction, while not beingconsumed or undergoing a permanent chemical change itself.

Carbonylation

The carbonylation step is performed contacting a feed stream 100comprising epoxide, and a carbonylation catalyst with carbon monoxide toprovide a reaction product stream 200 containing a carbonylation productformed from the epoxide.

Reactants

Turning first to the carbonylation reaction, the reactants may includevarious epoxides, including ethylene oxide, propylene oxide.

In certain embodiments, the epoxide starting material has formula I

where, R¹ and R² are each independently selected from the groupconsisting of: —H; optionally substituted C₁₋₆ aliphatic; optionallysubstituted phenyl; optionally substituted C₁₋₆ heteroaliphatic;optionally substituted 3- to 6-membered carbocycle; and optionallysubstituted 3- to 6-membered heterocycle, where R¹ and R² can optionallybe taken together with intervening atoms to form a 3- to 10-membered,substituted or unsubstituted ring optionally containing one or moreheteroatoms.

In some embodiments, R¹ is hydrogen. In some embodiments, R¹ is phenyl.In some embodiments, R¹ is optionally substituted C₁₋₆ aliphatic. Insome embodiments, R¹ is n-butyl. In some embodiments, R¹ is n-propyl. Insome embodiments, R¹ is ethyl. In some embodiments, R¹ is —CF₃. In someembodiments, R¹ is —CH₂Cl. In other embodiments, R¹ is methyl.

In some embodiments, R² is hydrogen. In some embodiments, R² isoptionally substituted C₁₋₆ aliphatic. In some embodiments, R² ismethyl.

In certain embodiments, R¹ and R² are taken together with interveningatoms to form a 3- to 10-membered, substituted or unsubstituted ringoptionally containing one or more heteroatoms. In some embodiments, R¹and R² are taken together with intervening atoms to form a cyclopentylor cyclohexyl ring.

In certain embodiments, an epoxide is chosen from the group consistingof: ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butyleneoxide, epichlorohydrin, cyclohexene oxide, cyclopentene oxide,3,3,3-Trifluoro-1,2-epoxypropane, styrene oxide, a glycidyl ether, and aglycidyl ester.

In certain embodiments, the epoxide is ethylene oxide.

In certain embodiments, the epoxide is propylene oxide.

In certain embodiments, the carbonylation step comprises the reactionshown in Scheme 2:

where, each of R¹ and R² is as defined above and described in classesand subclasses herein.

In certain embodiments, the carbonylation step comprises the reactionshown in Scheme 3:

where, R¹ is selected from the group consisting of —H and C₁₋₆aliphatic.

In certain embodiments, the carbonylation step comprises the reactionshown in Scheme 4:

In certain embodiments, the carbonylation step comprises the reactionshown in Scheme 5:

Additional reactants can include carbon monoxide, or a mixture of carbonmonoxide and another gas. In some embodiments, carbon monoxide isprovided in a mixture with hydrogen (e.g., Syngas). The ratio of carbonmonoxide and hydrogen can be any ratio, including by not limited to 1:1,1:2, 1:4, 1:10, 10:1, 4:1, or 2:1. In some embodiments, the carbonmonoxide is provided in mixture with gases as an industrial process gas.The carbon monoxide sources include but are not limited to: wood gas,producer gas, coal gas, town gas, manufactured gas, hygas, Dowson gas orwater gas, among others. In some embodiments, the carbon monoxide isprovided at super-atmospheric pressure. The quantity of carbon monoxideshould be supplied to effect efficient conversion of the epoxidestarting material to a beta-lactone.

Catalyst

In certain embodiments, a carbonylation catalyst comprises a metalcarbonyl complex. In some embodiments, a metal carbonyl complex has thegeneral formula [QM_(y)(CO)_(w)]^(x), where:

Q is any ligand and need not be present;

M is a metal atom;

y is an integer from 1 to 6 inclusive;

w is a number such as to provide the stable metal carbonyl; and

x is an integer from −3 to +3 inclusive.

In certain embodiments where a metal carbonyl complex has the formula[QM_(y)(CO)_(w)]^(x), M is selected from the group consisting of Ti, Cr,Mn, Fe, Ru, Co, Rh, Ni, Pd, Cu, Zn, Al, Ga and In. In certainembodiments, M is Co. In certain embodiments, a metal carbonyl complexis Co(CO)₄ ⁻.

In certain embodiments, a carbonylation catalyst further comprises aLewis acidic component. In certain embodiments, a Lewis acidic componentis cationic. In some embodiments, a carbonylation catalyst comprises ananionic metal carbonyl complex (e.g. x is a negative integer) and acationic Lewis acidic component. In certain embodiments, the metalcarbonyl complex comprises a carbonyl cobaltate and the Lewis acidiccomponent comprises a metal-centered cationic Lewis acid.

In certain embodiments, a metal-centered cationic Lewis acid is a metalcomplex of formula [M′(L)_(b)]^(c+), where:

M′ is a metal;

each L is a ligand;

b is an integer from 1 to 6 inclusive;

c is 1, 2, or 3; and

where, if more than one L is present, each L may be the same ordifferent.

In some embodiments where a metal-centered Lewis acid is a metal complexof formula [M′(L)_(b)]^(c+), M′ is selected from the group consistingof: a transition metal, a group 13 or 14 metal, and a lanthanide. Incertain embodiments, M′ is a transition metal or a group 13 metal. Incertain embodiments, is selected from the group consisting of aluminum,chromium, indium and gallium. In certain embodiments, M′ is aluminum. Incertain embodiments, M′ is chromium.

In certain embodiments, a metal-centered Lewis-acidic component of acarbonylation catalyst includes a dianionic tetradentate ligand. Incertain embodiments, a dianionic tetradentate ligand is selected fromthe group consisting of: porphyrin derivatives, salen derivatives,dibenzotetramethyltetraaza[14]annulene (“TMTAA”) derivatives,phthalocyaninate derivatives, and derivatives of the Trost ligand.

In some embodiments, a dianionic tetradentate ligand is ClTPP(meso-tetra(4-chlorophenyl)porphyrin). In some embodiments, a dianionictetradentate ligand is TPP (tetraphenylporphyrin). In some embodiments,a dianionic tetradentate ligand is a salen(N,N′-ethylenebis(salicylimine) ligand. In some embodiments, a dianionictetradentate ligand is a salph(N,N′-bis(salicylidene)-o-phenylenediamine) ligand. In some embodiments,a dianionic tetradentate ligand is a salcy(N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminocyclohexane) ligand.

In certain embodiments, a carbonylation catalyst comprises a carbonylcobaltate in combination with an aluminum porphyrin compound as aLewis-acidic component. In some embodiments, a carbonylation catalystcomprises [(TPP)Al][Co(CO)₄]. In some embodiments, a carbonylationcatalyst comprises [(ClTPP)Al][Co(CO)₄].

In certain embodiments, a carbonylation catalyst comprises a carbonylcobaltate in combination with a chromium porphyrin compound as aLewis-acidic component. In some embodiments, a carbonylation catalystcomprises [(TPP)Cr][Co(CO)₄]. In some embodiments, a carbonylationcatalyst comprises [(ClTPP)Cr][Co(CO)₄].

In certain embodiments, a carbonylation catalyst comprises a carbonylcobaltate in combination with a chromium salen compound as aLewis-acidic component. In some embodiments, a carbonylation catalystcomprises [(salcy)Cr][Co(CO)₄].

In certain embodiments, a carbonylation catalyst comprises a carbonylcobaltate in combination with a chromium salophen compound as aLewis-acidic component. In some embodiments, a carbonylation catalystcomprises [(salph)Cr][Co(CO)₄].

In certain embodiments, a carbonylation catalyst comprises a carbonylcobaltate in combination with an aluminum salen compound as aLewis-acidic component. In certain embodiments, a carbonylation catalystcomprises a carbonyl cobaltate in combination with an aluminum salophencompound as a Lewis-acidic component. In some embodiments, acarbonylation catalyst comprises [(salph)Al][Co(CO)₄].

In certain embodiments, a carbonylation catalyst further comprises oneor more electron donating groups. In certain embodiments, such electrondonating groups are solvent molecules. In some embodiments, an electrondonating group is a solvent molecule in which the catalyst, or a portionthereof, was synthesized. In certain embodiments, an electron donatinggroup is THF.

Solvents

In some embodiments, the carbonylation catalyst is present in a solvent.The solvent may be selected from any solvent, and mixtures of solvents.Additionally, beta-lactone may be utilized as a co-solvent. Solvents forthe catalyst include, but are not limited to, tetrahydrofuran (“THF”),sulfolane, N-methyl pyrrolidone, 1,3 dimethyl-2-imidazolidinone,diglyme, triglyme, tetraglyme, diethylene glycol dibutyl ether, ethylenecarbonate, propylene carbonate, butylene carbonate, dibasic esters,diethyl ether, acetonitrile, ethyl acetate, dimethoxy ethane, acetone,dioxane, THF modified with a C₁₋₃₂ alphatic chain. In general, aproticsolvents are suitable for the carbonylation reaction step. In someembodiments, the modified THF has the form:

wherein, R is an aliphatic, aromatic, ether, or ester group any of whichcontains more than four carbon atoms. In some embodiments, the modifiedTHF has the formula:

In some embodiments, the solvent includes a catalyst stabilizer. Variouscatalyst stabilizers include, but are not limited to isosorbide etherssuch as isosorbide dimethylether.

In some embodiments, the feed stream 100 includes a Lewis base additive.In some embodiments, such Lewis base additives can stabilize or reducedeactivation of the catalysts. In some embodiments, the Lewis baseadditive is a modified THF; 2,6-lutidine; imidazole, 1-methylimidazole4-dimethylaminopyridine, trihexylamine and triphenylphosphine.

In some embodiments, solvents suitable for the process have a boilingpoint higher than that of the beta-lactone produced by the carbonylationreaction. For example, in the carbonylation of ethylene oxide, the highboiling point solvent has a boiling point higher than about 108° C. at50 Torr since the beta-lactone produced (beta-propiolactone) has aboiling point of 108° C. at that pressure. For propylene oxide, thecorresponding beta-lactone (beta-butyrolactone) has a boiling point of86-87° C. at 50 Torr, and the high boiling solvent should have a higherboiling point than that.

In some embodiments, the solvent, or a mixture of solvents, is selectedto facilitate separation 2 of the beta-lactone from the reaction productstream. Generally, the separation is effected based on boiling pointdifferential between the solvent and the beta-lactone. In someembodiments, the boiling point of the solvent is higher than the boilingof the beta-lactone, when compared at the same pressure. In someembodiments, the boiling point of the solvent is at least about 20degrees Celsius higher than the boiling point of the beta-lactone whencompared at the same pressure. In some embodiments, the boiling point ofthe solvent is at least about 30 degrees Celsius higher than the boilingpoint of the beta-lactone when compared at the same pressure. In someembodiments, the boiling point of the solvent is at least about 40degrees Celsius higher than the boiling point of the beta-lactone whencompared at the same pressure. In some embodiments, the boiling point ofthe solvent is at least about 50 degrees Celsius higher than the boilingpoint of the beta-lactone when compared at the same pressure.

In some embodiments, the solvent has a boiling point that is lower thanthe boiling point of the beta-lactone when compared at the samepressure. In certain embodiments, the boiling point of the solvent isselected to be between about 30° C. and about 130° C. at atmosphericpressure. In certain embodiments, the boiling point of the solvent isselected to be between about 30 and about 100° C. at atmosphericpressure. In some embodiments, the boiling point of the solvent is atleast 10 degrees lower than the boiling point of the beta-lactone whencompared at the same pressure. In some embodiments, the boiling point ofthe solvent is at least 20 degrees lower than the boiling of thebeta-lactone when compared at the same pressure. In some embodiments,the boiling point of the solvent is at least 30 degrees lower than theboiling of the beta-lactone when compared at the same pressure. In someembodiments, the boiling point of the solvent is at least 40 degreeslower than the boiling of the beta-lactone when compared at the samepressure. In some embodiments, the boiling point of the solvent is atleast 50 degrees lower than the boiling of the beta-lactone whencompared at the same pressure. In some embodiments, the solvent iscomprised of a mixture of solvents one of which may have boiling pointhigher than the boiling of the beta-lactone, and the other solvent mayhave a boiling point lower than the boiling point of the beta-lactone.

In some embodiments, the reactants are completely soluble in the solventunder the reaction conditions. Additionally, the catalyst may be solublein the solvent under the reaction conditions. In some embodiments, thereactants or catalyst are only partially, or insoluble in the solventunder the reaction conditions. In some embodiments, only the catalyst issoluble in the solvent.

In some embodiments, the solvent is provided “fresh.” In someembodiments, the solvent is recycled after the separation step. Solventrecycling may include the addition of fresh solvent to the recyclestream.

In some embodiments, the solvent includes beta-lactone. In general, theuse of a beta-lactone as a co-solvent aides in eventual separation ofthe beta-lactone product from the non-beta-lactone solvent, if present.The separation of the beta-lactone from the remainder of the reactionproduct stream 200 becomes easier as the concentration of beta-lactonein reaction product stream increases.

Carbonylation Reaction Conditions

The carbonylation reaction conditions are selected based on a number offactors to effect conversion of the epoxide to a beta-lactone.Temperature, pressure, and reaction time influence reaction speed andefficiency. Additionally the ratio of reactants to each other and to thecatalyst effect reaction speed and efficiency.

In some embodiments, the reaction temperature can range from betweenabout −20° C., to about 600° C. In some embodiments, the reactiontemperature is about −20° C., about 0° C., about 20° C., about 40° C.,about 60° C., about 80° C., about 100° C., about 200° C., about 300° C.,about 400° C., about 500° C. or about , about 600° C. In someembodiments, the temperature is in a range between about 40° C. andabout 120° C. In some embodiments, the temperature is in a range betweenabout 40° C. and about 80° C. In some embodiments, the temperature is ina range between about 50° C. and about 70° C. In some embodiments, thereactants, catalyst and solvent are supplied to the reactor at standardtemperature, and then heated in the reactor. In some embodiments, thereactants are pre-heated before entering the reactor.

In some embodiments, the reaction pressure can range from between about50 psig to about 5000 psig. In some embodiments, the reaction pressureis about 100 psig, about 200 psig, about 300 psig, about 400 psig, about500 psig, about 600 psig, about 700 psig, about 800 psig, about 900psig, or about 1000 psig. In some embodiments, the pressure ranges fromabout 50 psig to about 2000 psig. In some embodiments, the pressureranges from about 100 psig to 1000 psig. In some embodiments, thepressure ranges from about 200 psig to about 800 psig. In someembodiments, the reaction pressure is supplied entirely by the carbonmonoxide. For example, the reactants, catalyst and solvent are chargedto the reactor at atmospheric pressure, or under a vacuum, and carbonmonoxide is added to the reactor to increase pressure to the reactionpressure. In some embodiments, all reactants, solvent and catalyst aresupplied to the reactor at reaction pressure.

In some embodiments, the ratio of catalyst to epoxide is selected, basedon other reaction conditions, so that the reaction proceeds in aneconomical and time-feasible manner. In some embodiments, the ratio ofcatalyst to epoxide is about 1:10000 on a molar basis. In someembodiments, the molar ratio of catalyst to epoxide is about 1:5000, isabout 1:2500, is about 1:2000, is about 1:1500, is about 1:1000, isabout 1:750, is about 1:500, is about 1:250, is about 1: 200, is about1: 150, or is about 1:100. In some embodiments, the concentration of theepoxide is in the range between about 0.1 M and about 5.0 M. In someembodiments, the concentration of the epoxide is in the range betweenabout 0.5 M and about 3.0 M.

In some embodiments, the reaction is maintained for a period of timesufficient to allow complete, near complete reaction of the epoxide tobeta-lactone or as complete as possible based on the reaction kineticsand or reaction conditions. In some embodiments, the reaction time ismaintained for about 12 hours, about 8 hours, about 6 hours, about 3hours, about 2 hours or about 1 hour. In some embodiments, the reactiontime is established as a residence time within the reactor 110. Thereaction can be halted by reducing the reactor temperature or pressure,withdrawing a particular reactant or introducing a quenching compound.The reaction may be halted at any point or any percentage conversion ofepoxide to beta-lactone. E.g., the reaction may be halted when 50% ofthe epoxide is converted to beta-lactone.

Carbonylation Reaction Products

As described above, the primary reaction product of the carbonylationreaction is a beta-lactone. Additionally, the reaction product stream200 may contain other reaction by-products, un-reacted reactants, aswell as catalyst and solvent. In some embodiments, the un-reactedreactants include epoxide or carbon monoxide. As such, the reaction maynot proceed to completion and may be considered a partial reaction.

In some embodiments, the amount of un-reacted epoxide is sufficient toprevent the formation of a succinic anhydride, a carbonylation reactionbyproduct. Without being bound by a particular theory, it is speculatedthat the second reaction converting the beta-lactone to succinicanhydride does not proceed, unless substantially all of the epoxide isconsumed. Thus a remaining portion of the epoxide feed to the reactorthat exits un-reacted appears to prevent the formation of succinicanhydride. In some embodiments, the reaction product stream 200 containsunconverted epoxide in an amount of at least about 5% epoxide, at leastabout 3% epoxide, at least about 1% epoxide or at least about 0.1%, byweight. In some embodiments, the reaction is performed in a continuousflow format and epoxide is added at a rate sufficient to maintain theconcentration in the above-described levels. In certain embodimentswhere the reaction is performed in a reactor where the reactionconditions vary over the volume of the reactor, the epoxide feed ischosen to maintain the lowest epoxide concentration in the reactor abovethe concentrations described above.

In some embodiments, by-product formation includes the formation ofanhydride having the formula:

where R¹ and R² correspond to the same groups in the epoxide feedstock.In some embodiments, by-product formation includes the formation of oneor more of the following compounds: crotonaldehyde, acrylic acid, 1,4dioxane, acrylic acid dimers and trimers, 2-hydroxyethyl acrylate, 2,5hexandienal, 3-oxacaprolactone, diethylene glycol monoacrylate,3-hydroxypropionic acid, diethylene glycol diacrylate, 5-valeroactoneand/or 2,6-dimethyl-1,3-dioxan-4-ol.

Reaction Mode

In some embodiments, the carbonylation reaction 1 is performed in acontinuous operation. The reactants are continuously fed to a reactor110. In some embodiments, the reactor 110 is stirred. In someembodiments, there is no stirring in the reactor 110, in someembodiments, reactor 110 incorporates one or more static mixers. In someembodiments, the reactor 110 includes a gas-entrainment impeller. Thereactants may be fed to the reactor 110 at standard temperature andpressure and then heated or pressurized to reaction conditions once inthe reactor 110. The reactor 110 itself may be any reactor conducive tocontinuous operation, including by not limited to a continuously stirredtank reactor or a tubular reactor. In some embodiments, the reactor 110is an adiabatic reactor, and/or an isothermal reactor. In someembodiments, the reactor pressure is constant. In some embodiments, thereactor pressure varies as the reaction progresses. In some embodiments,the reactor temperature varies as the reaction progress. In someembodiments, the reaction is performed in a batch operation. One ofordinary skill in the art will recognize the temperatures, pressures,catalyst ratios, concentrations of reactants, catalyst and solvents,flow rates can all be optimized or varied to achieve a given reactionoutcome.

In some embodiments, as described above, the various individual reactionproducts, or even the entire reaction product stream 200 can be recycledto the carbonylation reactor 110 or the feed stream 100 as a recycle. Insome embodiments, the reaction products are separated in to at least twostreams, as described below. Generally, at least one stream will containat least the solvent and catalyst and the other stream will contain atleast the beta-lactone product. Either or both of these streams may berecycled to the outset of the carbonylation reaction. In someembodiments, one stream will contain solvent and the other will containthe remainder of the reaction product stream 200.

In some embodiments, the catalyst and/or solvent stream is recycled tothe feed stream or to the carbonylation reactor. In some embodiments,the portion of the solvent and/or catalyst from the reaction productstream 200 recycled to the carbonylation reactor 110 or feed stream 100ranges from about 0% to about 100%. In some embodiments, the portion ofthe solvent and/or catalyst from the reaction product stream 200recycled to the carbonylation reactor 110 or feed stream 100 is about100%, about 90%, about 80%, about 70%, about 60%, about 50%, about 40%,about 30%, about 20%, about 10%, or about 0%. In some embodiments, adifferent percentage of the catalyst, as compared to the solvent isrecycled, i.e., the proportions of either the catalyst or solventcomponent do not need to be equal.

In some embodiments, a portion of the catalyst and/or solvent iswithdrawn from the recycling stream 500 as a waste 510. The portion ofthe catalyst and/or solvent withdrawn as waste 510, as compared to thetotal catalyst and/or solvent in the reaction product stream 200 may bein the range from about 0% to about 100%. The portion of the catalystand/or solvent withdrawn as waste 510, as compared to the total catalystand/or solvent in the reaction product stream 200 may be about 100%,about 90%, about 80%, about 70%, about 60, about 50%, about 40%, about30%, about 20%, or about 10%.

In some embodiments, fresh catalyst and or solvent 600 is fed to eitherthe recycling stream 500 or to the feed stream 100 in order to ensurethat carbonylation reaction continues. The solvent and or catalyst addedmay make up for solvent and/or catalyst lost in the reaction, withdrawnas waste 510, or exhausted and no longer useful. The portion of thecatalyst and/or solvent added, as compared to the total catalyst and/orsolvent in the reaction product stream may be in the range from about 0%to about 100% of the flow rate of the stream. The portion of thecatalyst and/or solvent added, as compared to the total catalyst and/orsolvent in the reaction product stream 200 may be about 100%, about 90%,about 80%, about 70%, about 60, about 50%, about 40%, about 30%, about20%, or about 10%.

In some embodiments, the beta-lactone is recycled to the carbonylationreactor 110 or the reactant feed stream 100. As discussed below thebeta-lactone 400 is generally separated from the reaction product stream200. In some embodiments, the portion of beta-lactone 420 from thereaction product stream 200 recycled to the carbonylation reactor orfeed stream ranges from about 0% to about 100%. In some embodiments, theportion beta-lactone from the reaction product stream 200 recycled tothe carbonylation reactor or feed stream is about 100%, about 90%, about80%, about 70%, about 60%, about 50%, about 40%, about 30%, about 20%,about 10%, about 0%. In some embodiments, 100% of the beta-lactonestream 400 is recycled to the reactor 110 or feed stream 100, until thepercentage of beta-lactone in the reaction product stream 200 reaches aspecified level. In some embodiments, the specified level ranges fromabout 5% to about 75%. In some embodiments, the level is about 5%, about10%, about 20%, about 30%, about 40%, about 50%, about 60%, or about75%.

The carbonylation step may begin without any beta-lactone present in thereaction product stream 200. After the start of the carbonylation, thebeta-lactone produced from the carbonylation step may accumulate in thereaction product stream 200, and in some embodiments, no beta-lactone isseparated from the reaction production stream 200 until the content ofthe beta-lactone in the reaction product stream 200 reaches a thresholdvalue. In certain embodiments, the threshold value is from about 5 toabout 10% by weight. In certain embodiments, the threshold value is fromabout 10% to about 20% by weight. In certain embodiments, the thresholdvalue is from about 20% to about 30% by weight. In certain embodiments,the threshold value is from about 30% to about 40% by weight. In certainembodiments, the threshold value is from about 40% to about 50% byweight. In certain embodiments, the threshold value is from about 50% toabout 60% by weight.

Separation

Another step in the process involves separating the reaction productstream 200 into at least two separate streams. At a minimum, thereaction product stream will be split into two separate streams, abeta-lactone stream 400 and a catalyst/solvent stream 500. Thebeta-lactone stream 400 will contain beta-lactone, but may also containother compounds carried over from the product reaction stream 200,including epoxide, carbon monoxide, solvent, catalyst, and reactionby-products. Similarly, the catalyst/solvent stream 500 may containprimarily catalyst and solvent, but may also include other compoundscarried over from the reaction product stream 200 including epoxide,carbon monoxide, beta-lactone, and reaction by-products.

In some embodiments, the separation is performed by exploiting theboiling point differential between the beta-lactone and the othercomponents of the reaction product stream 200, primarily the catalystand solvent. In some embodiments, the boiling point of the solvent ishigher than the boiling point of the beta-lactone. In some embodiments,the beta-lactone is volatilized (e.g., evaporated) from the reactionproduct stream, leaving behind a mixture of catalyst, solvent and othercompounds in the reaction product stream 200. In some embodiments, thisincludes exposing the reaction product stream 200 to reduced pressure.In some embodiments, this includes exposing reaction product stream 200to increased temperature. In some embodiments, this includes exposingthe reaction product stream 200 to both reduced pressure and increasedtemperature.

In some embodiments, the pressure is selected so that the boiling pointof the beta-lactone is reduced by about 5° C. as compared to the boilingpoint at atmospheric pressure. In some embodiments, the pressure isselected so the boiling point of the beta-lactone is reduced by about10° C. as compared to the boiling point at atmospheric pressure. In someembodiments, the pressure is selected so the boiling point of thebeta-lactone is reduced by about 20° C. as compared to the boiling pointat atmospheric pressure. In some embodiments, the pressure is selectedso the boiling point of the beta-lactone is reduced by about 50° C. ascompared to the boiling point at atmospheric pressure.

In some embodiments, the increased temperature is above the boilingpoint of the beta-lactone but below the boiling point of the solvent, atthe selected pressure. In some embodiments, the temperature is at leastabout 20° C. below the boiling point of the solvent. In someembodiments, the temperature is at least about 30° C. below the boilingpoint of the solvent. In some embodiments, the temperature is at leastabout 50° C. below the boiling point of the solvent.

In some embodiments, the reduced pressure is in the range from about 1Torr to about 760 Torr. In some embodiments, the pressure is in therange of about 1 Torr to about 400 Torr. In some embodiments, thepressure is in the range of about 5 Torr to about 200 Torr. In someembodiments, the pressure is in the range of about 10 Torr to about 100Torr. In some embodiments, the pressure is in the range of about 20 Torrto about 50 Torr. In some embodiments, the pressure is about 50 Torr,about 100 Torr, about 150 Torr, about 200 Torr, about 250 Torr, about300 Torr, about 400 Torr about 500 Torr, about 600 Torr or about 700Torr.

In some embodiments, the separation step is performed at a pressurebelow about 100 Torr and at a temperature above about 120° C. In someembodiments, the separation step is performed at a pressure below about50 Torr and at a temperature above about 100° C. In some embodiments,the separation step is performed at a pressure below about 50 Torr andat a temperature above about 50° C. In some embodiments, the separationstep is performed at a pressure below about 50 Torr and at a temperatureabove about 110° C. In some embodiments, the separation step isperformed at a pressure below about 50 Torr and at a temperature aboveabout 90° C. In some embodiments, the separation step is performed at apressure below about 20 Torr and at a temperature above about 60° C. Insome embodiments, the separation step is performed at a pressure belowabout 10 Torr and at a temperature above about 50° C.

In some embodiments, the separation may be effected in a sequence ofsteps, each operating at an independent temperature and pressure. E.g.,two steps may be used to obtain a more effective separation ofbeta-lactone, or a separate separation step may be used to isolatecertain reaction by-products. In some embodiments, when a mixture ofsolvents is used multiple separation steps may required to removeparticular solvents, individually or as a group, and effectively isolatethe beta-lactone.

In certain embodiments, the separation of the beta-lactone from thereaction product stream 200 is performed in two stages. In someembodiments the process includes a preliminary separation step to removeone or more components of the product stream having boiling points belowthat of the beta-lactone product.

In some embodiments, the preliminary separation step includes separatingthe reaction product stream 200 into a gas stream comprising carbonmonoxide, and unconverted epoxide; and a liquid stream comprising thebeta-lactone, and the carbonylation catalyst. In the second step ofseparation, the liquid stream is further separated into a beta-lactonestream 400 comprising a portion of the beta-lactone; and a catalystrecycling stream 500 comprising a remainder of the beta-lactone and thecarbonylation catalyst.

In some embodiments where one or more solvents with a boiling pointlower than that of the beta-lactone are present, the lower boilingsolvent may be volatilized (e.g., evaporated) from the reaction productstream in a preliminary separation step, leaving behind a mixturecomprising catalyst, beta-lactone, other solvents (if any) and othercompounds in the reaction product stream 200 which is then furthertreated to separate the beta-lactone stream.

In certain embodiments where the separation is performed in two stages,the first step of separation comprises exposing the reaction stream tomildly reduced pressure to produce the gas stream and the liquid stream.In certain embodiments where the separation is performed in two stages,the gas stream is returned to the carbonylation step.

In certain embodiments, the separation of the beta-lactone from thereaction product stream 200 is performed in three stages. In the firststep of separation, the reaction product stream 200 is separated into agaseous stream comprising carbon monoxide and a portion of the epoxide;and a liquid stream comprising a remainder of the epoxide, thebeta-lactone, and the carbonylation catalyst. In the second step ofseparation, the liquid stream is separated into an epoxide streamcomprising the remainder of the epoxide and, if present, any solventswith boiling points below that of the beta-lactone; and a second liquidstream comprising the beta-lactone, and the carbonylation catalyst. Inthe third step of separation, the second liquid stream is furtherseparated into a beta-lactone stream 400 beta-lactone stream 400comprising a portion of the beta-lactone; and a catalyst recyclingstream 500 comprising a remainder of the beta-lactone and thecarbonylation catalyst.

In certain embodiments where the separation is performed in threestages, the first step of separation comprises atmospheric venting ofthe reaction stream. In certain embodiments where the separation isperformed in three stages, the second step of separation comprisesexposing the liquid stream to mildly reduced pressure. In certainembodiments where the separation is performed in three stages, at leastone of the gaseous stream and the epoxide stream is returned to thecarbonylation step. In certain embodiments, the mildly reduced pressureis between about 100 Torr and 500 Torr. In certain embodiments, themildly reduced pressure is between about 200 Torr and 400 Torr.

Lewis Base Additive

The feed stream may further comprise a Lewis base additive. The Lewisacidic component in the carbonylation catalyst may be coordinated to oneof more Lewis base additives. The coordination of one or more Lewis baseadditives to the Lewis acidic component may stabilize the carbonylationcatalyst during the carbonylation step and/or the separation step.

In some embodiments, the feed stream further comprises one or more Lewisbase additives. In certain embodiments, a Lewis base additive isselected from nitrogen, phosphorous or oxygen Lewis bases. In certainembodiments, a Lewis base additive is selected from amines, phosphines,and ethers. In certain embodiments, a Lewis base additive is selectedfrom the group consisting of: modified THF; 2,6-lutidine; imidazole;1-methylimidazole and triphenylphosphine; 4-dimethylaminopyridine;trihexylamine.

Beta-lactone as Solvent

In some embodiments, the beta-lactone, the same chemical compound as thecarbonylation product from an epoxide, may be used as the only solventin the carbonylation reaction 1. In certain embodiments, thebeta-lactone is used as a co-solvent and one or more additional solventsare present in the reaction 1. In certain embodiments, the boiling pointof the other solvent present is greater than or less than the boilingpoint of the beta-lactone. In some embodiments, the beta-lactone is usedas a co-solvent and one or more low-boiling point solvents are presentin the process stream.

In some embodiments, where the methods of producing a beta-lactone froman epoxide comprise a carbonylation step 1 and a beta-lactone separationstep 2, the beta-lactone is a co-solvent and one or more high-boilingpoint solvents are present in the process stream. The carbonylation stepis performed by contacting a process stream comprising an epoxide, abeta-lactone, a high-boiling point solvent and a carbonylation catalystwith carbon monoxide to provide a reaction product stream 200 containinga carbonylation product from the epoxide, where the carbonylationproduct is the same chemical compound as the beta-lactone used as aco-solvent. The beta-lactone separation step 2 is performed by treatingthe reaction stream to conditions that cause volatilization of thebeta-lactone to produce a beta-lactone stream 400 comprising a portionof the beta-lactone, and a catalyst recycling stream 500 comprising thecarbonylation catalyst, the high-boiling point solvent, and a remainderof the beta-lactone.

In certain embodiments, where the beta-lactone is a co-solvent and oneor more higher boiling solvents are present in the feed stream 100, theseparation of the beta-lactone from the reaction product stream 200 isperformed in two stages. In the first step of separation, the reactionproduct stream 200 is separated into a gas stream comprising carbonmonoxide, and epoxide; and a liquid stream comprising beta-lactone,solvent, and carbonylation catalyst. In the second step of separation,the liquid stream is further separated into a beta-lactone stream 400comprising a portion of the beta-lactone; and a catalyst recyclingstream 500 comprising a remainder of the beta-lactone, the solvent, andthe carbonylation catalyst. At least one of the beta-lactone stream 400and the catalyst recycling stream 500 is returned to the first step ofthe process where it is recharged with additional epoxide and passedthrough the carbonylation reaction 1 again.

In certain embodiments, where the beta-lactone is a co-solvent and oneor more lower boiling solvents are present in the feed stream 100, theseparation of the beta-lactone from the reaction product stream 200 isperformed in two stages. In the first step of separation, the reactionproduct stream 200 is separated into a gas stream comprising carbonmonoxide, epoxide, and low boiling solvent; and a liquid streamcomprising beta-lactone and carbonylation catalyst and higher boilingsolvents if present. In the second step of separation, the liquid streamis further separated into a beta-lactone stream 400 comprising a portionof the beta-lactone; and a catalyst recycling stream 500 comprising aremainder of the beta-lactone, higher boiling solvent (if present), andthe carbonylation catalyst. At least one of the beta-lactone stream 400and the catalyst recycling stream 500 is returned to the first step ofthe process where it is recharged with additional epoxide and againpassed through the carbonylation reaction 1.

In certain embodiments, where the beta-lactone is a co-solvent and oneor more additional solvents are present in the process stream, theseparation of the beta-lactone from the reaction mixture is performed inthree stages. In the first step of separation, the reaction productstream 200 is separated into a gaseous stream comprising carbon monoxideand a portion of the epoxide; and a liquid stream comprising a remainderof the epoxide, the beta-lactone, the solvent, and the carbonylationcatalyst. In the second step of separation, the liquid stream isseparated into an epoxide stream comprising additional epoxide and lowerboiling solvent (if present); and a second liquid stream comprising thebeta-lactone, higher boiling solvent (if present), and the carbonylationcatalyst. In the third step of separation, the second liquid stream isfurther separated into a beta-lactone stream 400 comprising a portion ofthe beta-lactone; and a catalyst recycling stream 500 comprising aremainder of the beta-lactone, higher boiling solvent (if present), andthe carbonylation catalyst.

In some embodiments, the reaction product stream may be treated beforethe separation 2 is accomplished. Non-limiting examples of additionaltreatment 21 includes heating, cooling, decompressing, pressurizing,diluting, concentrating, degassing, filtering, purifying and anycombination of these. Additionally, gaseous components of the reactionproduct stream (e.g., carbon monoxide, epoxide) may be vented from thereaction product stream 200 in conjunction with one or more treatments21.

In some embodiments, the separation streams (e.g., the beta-lactonestream 400 and the catalyst solvent stream 500) are further treatedbefore other operations. Non-limiting examples of additional treatment41, 51 include heating, cooling, decompressing, pressurizing, diluting,concentrating, degassing, filtering, purifying, removing spent catalyst,removing reaction byproducts, adding fresh catalyst, adding one or morecatalyst components, adding solvent, and any combination of these.Additionally, gaseous components of the beta-lactone stream 400 and thecatalyst solvent stream 500 (e.g., carbon monoxide, epoxide) may bevented from the beta-lactone stream 400 and the catalyst solvent stream500 in conjunction with one or more treatments 41, 51.

As described above, the beta-lactone may be recycled back to thecarbonylation reactor 110, or the feed stream 100. In some embodiments,not all of the beta-lactone stream 420 is recycled. Some of thebeta-lactone stream is withdrawn 430 and carried to acrylation step 3.

Acrylation

In some embodiments, the beta-lactone stream 430 resulting from theseparation step 2 is optionally carried onto an acrylate productionstep. The acrylate production step is discussed in more detail below.The beta-lactone stream 430 may optionally be processed in a number waysprior to the acrylate production step. This processing can include, butis not limited to: heating, cooling, or compressing the stream;condensing the stream to a liquid state and carrying forward the liquid;adding a polymerization inhibitor to the stream; condensing selectedcomponents to a liquid state and carrying forward the remaining gaseouscomponents; condensing selected components to a liquid state andcarrying forward the liquefied components; scrubbing the stream toremove impurities; and any combination of two or more of these.

Turning next to the acrylate production step, the isolated beta-lactonestream 430 discussed above is carried onward to convert the beta lactonecontained therein to acrylic acid or an acrylic acid derivative. Asdiscussed above, in some embodiments, the isolated beta-lactone stream430 may undergo additional processing steps between the separation step2 and may enter the acrylate production stage of the process as a gas oras a liquid. The acrylate production step itself may be performed ineither the gas phase or the liquid phase and may be performed eitherneat, or in the presence of a carrier gas, solvent or other diluent.

In certain embodiments, the acrylate production step is performed in acontinuous flow format. In certain embodiments, the acrylate productionstep is performed in a continuous flow format in the gas phase. Incertain embodiments, the acrylate production step is performed in acontinuous flow format in the liquid phase. In certain embodiments, theacrylate production step is performed in a liquid phase in a batch orsemi-batch format.

The acrylate production step may be performed under a variety ofconditions. In certain embodiments, the reaction may be performed in thepresence of one or more catalysts that facilitate one or more steps inthe transformation of the beta lactone intermediate to the acrylateproduct. Many catalysts known in the art can be used, or adapted forthis step. In some embodiments, conditions include reaction withdehydrating agents such as sulfuric acid, phosphoric acid or estersthereof as described in U.S. Pat. Nos. 2,352,641; 2,376,704; 2,449,995;2,510,423; 2,623,067; 3,176,042, and in British Patent No. GB 994,091,the entirety of each of which is incorporated herein by reference.

In other embodiments, the lactone can be reacted with a halogeniccompound to yield a beta halo acid, beta halo ester, or beta halo acidhalide which may then undergo dehydrohalogenation and/or solvolysis toafford the corresponding acrylic acid or acrylic ester. In certainembodiments, conditions disclosed in U.S. Pat. No. 2,422,728(incorporated herein by reference) are used in this process.

In other embodiments, the acrylate production may be base catalyzed, seefor example Journal of Organic Chemistry, 57(1), 389-91(1992) andreferences therein, the entirety of which is incorporated herein byreference.

In certain embodiments, the acrylate production stage of the process maybe performed by combining the isolated beta-lactone stream 430 from thepreviously described steps with an alcohol vapor and passing the mixturein the gas phase through a column of an solid, or solid supportedpromoter that affects the conversion to an acrylic ester. In certainembodiments, this process is performed over a promoter includingactivated carbon according to the methods of US Patent No. 2,466,501 theentirety of which is incorporated herein by reference.

In some embodiments, the beta lactone in the isolated beta-lactonestream 430 is allowed to polymerize and acrylic acid or derivativesthereof are obtained by decomposition of the polymer. In certainembodiments, the beta lactone is propiolactone and the polymer ispoly(3-hydroxy propionic acid) (3-HPA). In certain embodiments, the3-HPA is formed and decomposed using the methods described in U.S. Pat.Nos. 2,361,036; 2,499,988; 2,499,990; 2,526,554; 2,568,635; 2,568,636;2,623,070; and 3,002,017, the entirety of each of which is incorporatedherein by reference.

In certain embodiments, the beta lactone product stream is reacted witha nucleophile of the formula Y—H. In certain embodiments, Y is selectedfrom the group consisting of halogen; —OR¹³; —NR¹¹R¹²; and —SR¹³, whereR¹¹, R¹², and R¹³ are independently selected from the group consistingof: —H; optionally substituted C₁₋₃₂ aliphatic; optionally substitutedC₁₋₃₂ heteroaliphatic; optionally substituted 3- to 14-memberedcarbocycle; and optionally substituted 3- to 14-membered heterocycle,and where R¹¹ and R¹² can optionally be taken together with interveningatoms to form an optionally substituted ring optionally containing oneor more heteroatoms.

In certain embodiments, the beta lactone product stream is reacted witha nucleophile of the formula Y—H to afford an acrylate having theformula II:

In certain embodiments, Y—H is an amine having the formula R¹¹R¹²N—H,and the product is an acrylamide. In certain embodiments, conditionsdisclosed in U.S. Pat. Nos. 2,548,155; 2,649,438; 2,749,355; and3,671,305, the entirety of each of which is incorporated herein byreference .

In certain embodiments, the beta lactone product stream is reacted witha nucleophile of the formula Y—H to afford an acid having the formulaIII:

In certain embodiments, compounds of formula III are obtained usingconditions disclosed in U.S. Pat. Nos. 2,449,992; 2,449,989; 2,449,991;2,449,992; and 2,449,993, the entirety of each of which is incorporatedherein by reference.

In certain embodiments, where the beta lactone product stream is reactedwith a nucleophile of the formula Y—H to afford an acid having theformula III, and Y is —OR¹³; —NR¹¹R¹²; or —SR¹³, the acid is dehydratedto yield an acrylate of formula II.

In certain embodiments, the conversion of III to II is performedaccording to the methods and conditions of U.S. Pat. No. 2,376,704 theentirety of which is incorporated herein by reference.

In certain embodiments, the acrylate product stream resulting from theproceeding steps may undergo additional purification steps. In certainembodiments, the stream is purified according to methods disclosed inU.S. Pat. Nos. 3,124,609; 3,157,693; 3,932,500; 4,82,652; 6,048,122;6,048,128; 6,084,128; and 6,207,022, the entirety of each of which isincorporated herein by reference.

EXAMPLES

Several acronyms and abbreviations are used throughout this section. Forclarity the most commonly are presented here. Ethylene Oxide (“EO”);Carbon Monoxide (“CO”); Propylene Oxide (“PO”); Turnover Frequency(“TOF”); Propiolactone or beta-Propiolactone (“PL:); Butyrolactone orbeta-Butyrolactone (“BBL”); concentrations are indicated with brackets,e.g., concentration of Propiolactone [PL]; Freeze-Pump-Thaw (“FPT”).

Example 1 Temperature and Pressure Effect

Temperature and pressure effect on carbonylation of EO was studied byvarying temperature and pressure.

TABLE 1 Temperature and pressure effect on catalyst activity in THF temppressure yield (%) rxn # (° C.) (psi) EO^(c) Ald.^(c) PL^(c) SA^(c)29-39^(a) 30 200 69 0 22 0 29-56^(b) 60 200 0.4 5 92 0.1 29-59^(b) 30600 44 0 44 0 29-54^(b) 60 600 0 0 88 8 29-57^(b) 60 600 0 trace 81 1329-66^(b) 45 400 25 trace 73 0 * Conditions: EO (1.8M; Arc), catalyst:[(ClTPP)Al][Co(CO)₄] (60 μmol), EO:cat = 1500:1, total volume: 50 mL (inTHF), agitation speed: 730 rpm, reaction time: 3 h, and internalstandard: hexamethylbenzene. ^(a)catalyst: hexamethylbenzene (0.5 mmol;Alfa Aesar (Ward Hill, MA), and THF (received from the column; FPT *2)^(b)catalyst: hexamethylbenzene (1.0 mmol; TCI), and THF (dried over 4 Åsieves and stored in the glove box; FPT *2) ^(c)EO (ethylene oxide),Ald. (acetaldehyde), PL (propiolactone), and SA (succinic anhydride)

Pressure increase from 200 psi of CO to 600 psi at 30° C. doubled theyield of propiolactone (see 29-39 and 29-59 in Table 1). When thereaction temperature was increased from 30° C. to 60° C. at 200 psi ofCO (see 29-39 and 29-54), the reaction went to completion and the yieldof propiolactone more than tripled.

Reaction Procedure A; Reaction Procedure for Carbonylation of EthyleneOxide in THF

A 300 mL Parr reactor was dried overnight under vacuum. In a nitrogenglovebox, the reactor was charged with [(ClTPP)Al][Co(CO)4] (66 mg, 60mmol), hexamethylbenzene (162 mg, 1 0 mmol), and THF (dried over 4 Åmolecular sieves, and freeze, pump, and thaw 3 times), then closed andremoved from the glovebox. Ethylene oxide was vacuum transferred to atransfer vessel from EO lecture bottle. The Parr reactor was cooled to−78° C. and high vacuum was applied to the reactor. The vacuum wasdisconnected from the reactor, and the transfer vessel was connected tothe Parr reactor to allow EO to be vacuum transferred from the transfervessel to the reactor at −78° C. The reaction mixture was warmed toambient temperature and saturated with CO by pressurizing the reactorwith CO to three fourth of the desired CO pressure (e.g. 150 psi), thenheated to the desired temperature. After the temperature of reactionmixture reached the desired temperature, the reactor was pressurized tothe desired pressure (e.g. 200 psi). The reaction mixture was agitatedfor 3 h. The reactor was cooled to <0° C. and vented. A portion ofreaction mixture was sampled and analyzed by 1H NMR in CDCl₃.

Example 2 Catalyst Loading

Catalyst concentration was doubled to see if the activity proportionallyincreases with the catalyst concentration increase (November 29-39 and29-43 in Table 2).

TABLE 2 Reaction time and catalyst loading (30° C.; 200 psi CO) timecat. yield (%) TOF rxn # (h) (mmol) EO/cat EO Ald. PL SA (/h) 29-39 30.06 1500 69 0 22 0 110 29-38 6 0.06 1500 63 0 28 0 70 29-43 3 0.12 75060 0 32 0 80 * Conditions: EO (1.8M), catalyst: [(ClTPP)Al][Co(CO)₄] (60μmol), EO:cat = 1500:1, total volume: 50 mL (in THF), agitation speed:730 rpm, reaction time: 3 h, internal standard: hexamethylbenzene(0.5mmol; Alfa Aesar), and THF (received from the column; FPT *2)

The same reaction procedure as Procedure A was used except for thecatalyst loading.

Example 3 Evaluation of Syngas as a CO Source

Syngas is a cost-effective source for CO, and the use of syngas canreduce the cost of industrial scale ethylene oxide carbonylation. A oneto one mixture of CO and H₂ was used to test ethylene oxidecarbonylation (November 29-72 and November 29-73 in Table 3). Nohydroformylation product, 3-hydroxypropanaldehyde or 1,3-propanediol,was found in ¹H NMR spectrum of the reaction mixture.

TABLE 3 Syngas temp pressure yield (%) rxn # CO:H₂ (° C.) (psi) EO Ald.PL SA 29-39^(a) 100% 30 200 69 0 22 0 CO 29-72^(b) 1:1 30 200 47 0 8 029-73^(b) 1:1 30 400 53 0 10 0 * Conditions: EO (1.8M; Arc), catalyst:[(ClTPP)Al][Co(CO)₄] (60 μmol), EO:cat = 1500:1, total volume: 50 mL (inTHF), agitation speed: 730 rpm, reaction time: 3 h, and internalstandard: hexamethylbenzene. ^(a)catalyst: hexamethylbenzene (0.5 mmol;Alfa Aesar), and THF (received from the column; FPT *2) ^(b)catalyst:hexamethylbenzene (1.0 mmol; TCI), and THF (dried over 4 Å sieves andstored in the glove box; FPT *2)

The same reaction procedure as Procedure A was used except for the COsource. The 50:50 mixture of CO and H₂ was purchased from Airgas(Radnor, PA) (Certified Grade; 50% Research Plus Grade CO and 50%Research Grade H₂).

Example 4 Carbonylation of Ethylene Oxide in High Boiling Point Solvents

The ethylene oxide carbonylation in high boiling point solvents wasstudied. In the continuous flow process of propiolactone production,propiolactone will be isolated by distillation from the reactionmixture, and this process needs a high boiling point solvent. Top threecandidates for the high boiling point solvent were chosen based on theresults from propylene oxide carbonylation. The catalyst activities ofthe reactions in three high boiling point solvents are about one fifthof the catalyst activity in THF (Table 4).

TABLE 4 High boiling solvents temp pressure yield (%) rxn # solvent (°C.) (psi) EO Ald. PL SA 29-56 THF 60 200 0.4 5 92 0.1 29-62 DBE 60 20052 1.7 21 0 29-63 Sulfolane 60 200 41 ? 22 ? 29-64 Pr. Carb. 60 200 52trace 15 0 * Conditions: EO (1.8M; Arc), catalyst: [(ClTPP)Al][Co(CO)₄](60 μmol), EO:cat = 1500:1; reaction time: 3 h; THF, DBE, sulfolane andpropiocarbonate (dried over 4 Å sieves; ; FPT *2); and internalstandard: hexamethylbenzene (1.0 mmol; TCI).

Reaction Procedure B; Reaction Procedure for Carbonylation of EthyleneOxide in High Boiling Point Solvents

A 300 mL Parr reactor was dried overnight under vacuum. In a nitrogenglovebox, the reactor was charged with [(ClTPP)Al][Co(CO)4] (66 mg, 60mmol), and hexamethylbenzene (162 mg, 1.0 mmol), then closed and removedfrom the glovebox. Solvent (DBE, sulfolane or propylene carbonate; eachsolvent was dried over 4 Å molecular sieves and degassed) was added viasyringe under N₂. Ethylene oxide was vacuum transferred to a transfervessel from EO lecture bottle. The Parr reactor was cooled to −78° C.and high vacuum was applied to the reactor. The vacuum was disconnectedfrom the reactor, and the transfer vessel was connected to the Parrreactor to allow EO to be vacuum transferred from the transfer vessel tothe reactor at −78° C. The reaction mixture was warmed to ambienttemperature and saturated with CO by pressurizing the reactor with CO tothree fourth of the desired CO pressure (e.g. 150 psi), then heated tothe desired temperature. After the temperature of reaction mixturereached the desired temperature, the reactor was pressurized to thedesired pressure (e.g. 200 psi). The reaction mixture was agitated for 3h. The reactor was cooled to <0° C. and vented. A portion of reactionmixture was sampled and analyzed by 1H NMR in CDCl₃.

Example 5 EO Carbonylation in DBE (Design of Experiments)

The goal of DOE was to find major factors influencing the activity ofthe catalyst ([(ClTPP)Al(THF)₂][Co(CO)₄]) and to find the optimumreaction conditions for running the EO carbonylation in DBE. DBE (amixture of dimethyl succinate, dimethyl glutarate, and dimethyl adipate)was selected as the solvent of choice because the reaction in DBE showedthe highest β-propiolactone (PL) yield among the preliminary highboiling point solvent screening reactions. Statistical software, JMP®8.0, (SAS Software, Cary, N.C.) was used to design and analyze DOE runs.The experiment design was created using a screening design. Sixcontinuous factors ([EO], temperature, CO pressure, agitation speed,time, and EO/catalyst ratio) were chosen for the DOE (Table 8).Fractional factorial type design having the six continuous factors wascreated. The design required 16 runs to analyze the effects of the sixfactors and some 2 factor interactions. Additional 3 center point runswere included to measure the variability of the DOE runs (Table 5).

TABLE 5 DOE factors; EO carbonylation in DBE Exp [EO] temp pressagitation time # Pattern (M) EO/cat. (° C.) (psi) (rpm) (h) 1 +−−−−+ 1.8500 50 200 500 4 2 +++−−− 1.8 1500 80 200 500 2 3 0 1.4 1000 65 400 7503 4 +−−++− 1.8 500 50 600 1000 2 5 −−+−++ 1.0 500 80 200 1000 4 6 0 1.41000 65 400 750 3 7 −++−−+ 1.0 1500 80 200 500 4 8 ++−+−− 1.8 1500 50600 500 2 9 −−−−−− 1.0 500 50 200 500 2 10 −++++− 1.0 1500 80 600 1000 211 ++++++ 1.8 1500 80 600 1000 4 12 +−++−+ 1.8 500 80 600 500 4 13−−++−− 1.0 500 80 600 500 2 14 0 1.4 1000 65 400 750 3 15 −+−−+− 1.01500 50 200 1000 2 16 +−+−+− 1.8 500 80 200 1000 2 17 −+−+−+ 1.0 1500 50600 500 4 18 −−−+++ 1.0 500 50 600 1000 4 19 ++−−++ 1.8 1500 50 200 10004 * Conditions: EO: purchased from Arc, catalyst: [(ClTPP)Al][Co(CO)₄],total volume: 60 mL, solvent: DBE (purchased from Aldrich; dried over 4Å sieves; FPT *3; and stored in the glove box), internal standard:1,4-di-tert-butylbenzene (1 mmol)

TABLE 6 DOE responses; EO carbonylation in DBE Exp Y_(Ald) Y_(PL) Y_(SA)Y_(EO) TOF_(PL) TOF_(CO) # Pattern (%) (%) (%) (%) (h⁻¹) (h⁻¹) 1 +−−−−+0.6 36.6 0 28.1 46 46 2 +++−−− 12.3 20.0 0 20.5 150 150 3 0 0.4 19.4 044.5 65 65 4 +−−++− 0 34.5 0 40.7 86 86 5 −−+−++ 30.3 0 54.2 0 0 136 6 00.6 23 0 38 77 77 7 −++−−+ 35 35.5 0 0.8 133 133 8 ++−+−− 0 6.2 0 40.547 47 9 −−−−−− 0.4 20 0 42.4 50 50 10 −++++− 2.4 20 0 39.2 150 150 11++++++ 3.3 33.2 0 27.8 125 125 12 +−++−+ 5.5 23.6 50.8 0.4? 30 157 13−−++−− 5.4 0.7 68.8 0 2 346 14 0 0.4 23.6 0 26.5 79 79 15 −+−−+− 0 5.3 041.8 40 40 16 +−+−+− 24.9 0 61.9 0 0 310 17 −+−+−+ 0 6.8 0 50.9 26 26 18−−−+++ 0 32.4 0 37 41 41 19 ++−−++ 0 10.7 0 51.9 40 40 * Y_(Ald):acetaldehyde yield based on ¹H NMR integration of acetaldehyde andinternal standard (di-tert-butylbenzene); Y_(PL): beta-propiolactoneyield; Y_(SA): succinic anhydride yield; Y_(EO): percentage of EO leftin the reaction mixture; TOF_(PL) = Y_(PL)*[EO]₀/(time*[cat]); andTOF_(CO) = (Y_(PL)*[EO]₀ + Y_(SA)*[EO]₀)/(time*[cat]).

Reaction Procedure C; Reaction Procedure for Carbonylation of EthyleneOxide in DBE (DOE Runs; see Figures Below)

A 300 mL Parr reactor was dried overnight under vacuum. In a nitrogenglovebox, the reactor was charged with 1,4-di-tert-butylbenzene (190 mg,1.0 mmol), and DBE (dried over 4 Å molecular sieves, and freeze, pump,and thaw 3 times). The shot tank which is connected to the reactor wascharged with [(ClTPP)Al][Co(CO)₄] and 10 mL of DBE. The reactor wasclosed and removed from the glovebox. Ethylene oxide was vacuumtransferred to a transfer vessel from EO lecture bottle. The Parrreactor was cooled to −78° C. and high vacuum was applied to thereactor. The vacuum was disconnected from the reactor, and the transfervessel was connected to the Parr reactor to allow EO to be vacuumtransferred from the transfer vessel to the reactor at −78° C. Thereaction mixture was warmed to ambient temperature and the agitator wasturned on. The reactor was heated to the desired temperature. After thetemperature of reaction mixture reached the desired temperature, theshot tank was pressurized to three fourth of the desired CO pressure.The shot tank was open to the reactor to allow the catalyst solution tobe added to the reactor. The reactor was pressurized to the desiredpressure. The reaction mixture was agitated for indicated periods, andthen it was cooled to −20° C. and vented. A portion of reaction mixturewas sampled and analyzed by ¹H NMR in CDCl₃.

The responses for the DOE (Table 9) were acetaldehyde yield (%), PLyield (%), succinic anhydride (SA) yield (%), EO (%), TOF_(PL) ((PLyield*[EO]₀)/(time*[cat])) and TOF_(CO) (CO insertion per catalyst perhour).

Example 6 EO Carbonylation in Sulfolane at 80° C.

EO carbonylation in sulfolane was conducted at 80° C. to compare thereaction result with the carbonylations in DBE at 80° C. (Table 7). Thereaction was run at the same reaction conditions as DOE run #13.Although, the CO insertion rate (TOF_(CO)) seems to be slower than thatof DOE run #13, high PL yield and TOF_(PL) suggests that sulfolane isthe better solvent for ethylene oxide carbonylation.

TABLE 7 [EO] temp press agitate time Y_(Ald) Y_(PL) Y_(SA) Y_(EO)TOF_(PL) (M) EO/cat (° C.) (psi) (rpm) (h) (%) (%) (%) (%) (h⁻¹) 1.0 50080 600 500 2 2.4 80.4 0 1.1 201 * Conditions: EO: purchased from Arc,catalyst: [(ClTPP)Al][Co(CO)₄], total volume: 60 mL, solvent: sulfolane(purchased from Aldrich; dried over 4 Å sieves; FPT *3), internalstandard: 1,4-di-tert-butylbenzene (1 mmol), the same reaction procedureas DOE runs.

The same reaction procedure as Procedure C was used except for thesolvent. Sulfolane was purchased from Aldrich, dried over 4 Å sieves andFPT *3.

Example 7 Screening [(salph)M][Co(CO)₄] Catalysts

Catalysts having the structures shown in Formulas IV & V, were screenedas catalyst candidate for EO carbonylation. While [(salph)Cr][Co(CO)₄]showed more than twice the activity of [(ClTPP)Al][Co(CO)₄],[(salph)Al][Co(CO)₄] showed much lower activity compared to[(salph)Cr][Co(CO)₄] (Table 11). The NMR analysis of the catalyst showedthat the catalyst batch contains impurities.

TABLE 8 temp press Y_(Ald) Y_(PL) Y_(SA) Y_(EO) TOF Exp. # catalystEO/cat (° C.) (psi) (%) (%) (%) (%) (h⁻¹) 29-85 ClTPPAl^(a) 1000 65 4000.6 23 0 38 77 29-102 salphCr^(b) 1000 65 400 1.4 55.1 0 21 184 29-104salphAl^(c) 1000 65 400 0 3.5 0 44.1 12 ^(a)ClTPPAl =[(ClTPP)Al][Co(CO)₄] ^(b)salphCr = [(salph)Cr][Co(CO)₄] ^(c)salphAl =[(salph)Al][Co(CO)₄] * Conditions: EO: purchased from Arc, [EO] = 1.4M,total volume: 60 mL, solvent: DBE (purchased from Aldrich; dried over 4Å sieves; FPT *3), internal standard: 1,4-di-tert-butylbenzene (1 mmol),the same reaction procedure as DOE runs.

The same reaction procedure as Procedure C was used except for thecatalyst.

Example 8 React-IR Experiments in DBE and Sulfolane

A react-IR probe was used to monitor EO carbonylations in DBE andsulfolane. Two reactions in sulfolane were monitored by react-IR(November 29-105 and November 29-108; Table 9). Absorbance of PL (1823cm⁻¹), EO (867 cm⁻¹), and acetaldehyde (1724 cm⁻¹) was monitored duringthe reactions and absorbance versus time plot is shown in FIGS. 3 and 4.

TABLE 9 [EO] temp press agitate Y_(Ald) Y_(PL) Y_(SA) Y_(EO) Exp. # (M)EO/cat (° C.) (psi) (rpm) (%) (%) (%) (%) 29-105 1.0 500 80 600 500 3.853.6 0 1.4 29-108 1.8 500 80 600 500 7.9 46.8 0 3.2 * Conditions: EO:purchased from Arc, catalyst: [(ClTPP)Al][Co(CO)₄] total volume: 108 mL,solvent: sulfolane (purchased from Aldrich; dried over 4 Å sieves; FPT*3), internal standard: 1,4-di-tert-butylbenzene (1 mmol)

Reaction Procedure D; Reaction Procedure for Carbonylation of EthyleneOxide in DBE Monitored by React-IR

In a nitrogen glovebox, a 300 mL Parr reactor equipped with IR sentinelprobe was charged with 1,4-di-tert-butylbenzene (190 mg, 1.0 mmol). Thereactor was closed and removed from the glovebox. The IR sentinel probewas connected to a react IR (Mettler-Toledo, Columbus, Ohio). Sulfolane(dried over 4 Å molecular sieves, and degassed) was added to the reactorvia syringe under N₂. Ethylene oxide was vacuum transferred to atransfer vessel from EO lecture bottle. The Parr reactor was cooled 0°C. and high vacuum was applied to the reactor. The vacuum wasdisconnected from the reactor, and the transfer vessel was connected tothe Parr reactor to allow EO to be vacuum transferred from the transfervessel to the reactor. The reaction mixture was warmed to ambienttemperature and the agitator was turned on. A shot tank was connected tothe reactor and was charged with [(ClTPP)Al][Co(CO)₄] and 10 mL ofsulfolane. The reactor was heated to the desired temperature. After thetemperature of reaction mixture reached the desired temperature, theshot tank was pressurized to three fourth of the desired CO pressure.The shot tank was open to the reactor to allow the catalyst solution tobe added to the reactor. The reactor was pressurized to the desiredpressure. The reaction was monitored by react-IR.

No succinic anhydride (FIG. 3; Table 9) was formed even long after PLformation plateaued.

The EO carbonylation in DBE was also monitored using react-IR (Table10). The reaction procedure for this reaction was modified from the DOEexperiment procedure to avoid acetaldehyde formation. The catalystsolution in DBE was pressurized to 200 psi for 40 min in a Parr reactor.The temperature was increased from room temperature to 80° C., while thereactor was pressurized to 200 psi. EO was added to a shot tank, andthen the shot tank was pressurized with CO to 600 psi. EO was added tothe Parr reactor by opening the valve connecting the shot tank and theParr reactor. Despite the pre-saturation of the reaction mixture withCO, ¹H NMR analysis of the sample taken after the reaction shows thatacetaldehyde was produced in the reaction.

TABLE 10 [EO] temp press agitate Y_(Ald) Y_(PL) Y_(SA) Y_(EO) Exp. # (M)EO/cat (° C.) (psi) (rpm) (%) (%) (%) (%) 29-112 1.0 500 80 600 500 7.90 62.7 0 * Conditions: solvent: DBE (purchased from Aldrich; dried over4 Å sieves; FPT *3), EO: purchased from Arc, catalyst:[(ClTPP)Al][Co(CO)₄], total volume: 100 mL, internal standard:1,4-bis(trimethylsilyl)benzene (1.11 mmol).The same reaction procedure as Procedure D was used except for thesolvent.

Absorbance of PL (1823 cm⁻¹), EO (867 cm⁻¹), and SA (1791 cm⁻¹) isplotted as a function time and shown in FIG. 5. Acetaldehyde (1724 cm⁻¹)peak was overlapped with DBE peaks and could not be monitored. The plotshows that the 2nd carbonylation (conversion from PL to SA) undergoesmuch faster than 1st carbonylation (from EO to PL) in DBE.

Example 9 Effect of Initial Addition of β-Propiolactone (PL)

Externally adding PL into the reaction mixture before the start of thereaction was tested using react-IR. Using PL as a solvent or aco-solvent is an attractive idea for the commercial scale process of EOcarbonylation because it can facilitate the separation of PL. However,PL itself can react with CO to produce SA. The 1.0 M PL solution insulfolane containing the catalyst was pre-saturated with 200 psi of COfor 40 min, and then EO was added to the catalyst solution with 400 psiof CO.

TABLE 11 [EO] temp press agitate Y_(Ald) Y_(PL) Y_(SA) Y_(EO) Exp. # (M)EO/cat (° C.) (psi) (rpm) (%) (%) (%) (%) 29-110 1.8 500 80 400 500 9.134.5 0 5.0 * Conditions: EO: purchased from Arc, catalyst:[(ClTPP)Al][Co(CO)₄], total volume: 100 mL, solvent: sulfolane(purchased from Aldrich; dried over 4 Å sieves; degassed), PL (purchasedfrom Aldrich; dried over 4 Å sieves; degassed), internal standard:1,4-bis(trimethylsilyl)benzene (1.11 mmol).

Reaction Procedure E; Reaction Procedure for Carbonylation of EthyleneOxide in PL and Sulfolane Monitored by React-IR

In a nitrogen glovebox, a 300 mL Parr reactor equipped with IR sentinelprobe was charged with 1,4-bis(trimethylsilyl)benzene (1.11 mmol) and[(ClTPP)Al][Co(CO)₄] (0.36 mmol). The reactor was closed and removedfrom the glovebox. The IR sentinel probe was connected to a react IR.Sulfolane (dried over 4 Å molecular sieves, and degassed) and PL(purchased from Aldrich; dried over 4 Å sieves; FPT*3), were added tothe reactor via syringe under N₂. The agitator was turned on, and thereaction mixture was heated to the desired temperature. A shot tank wasconnected to the reactor and was charged with ethylene oxide. After thetemperature of reaction mixture reached the desired temperature, theshot tank was pressurized to three fourth of the desired CO pressure.The shot tank was open to the reactor to allow EO to be added to thereactor. The reactor was pressurized to the desired pressure. Thereaction was monitored by react-IR.

No formation of SA was observed in ¹H NMR, which means that PL did notreact with CO in the presence of the catalyst during the pre-saturationstep and during the reaction (temperature was ramped up from roomtemperature to 80° C. for 40 min during the pre-saturation step).

The absorbance of PL, EO, and acetaldehyde was monitored during thereaction (FIG. 6). Even after the pre-saturation with CO, the absorbanceof acetaldehyde rose quickly when EO was added, and then slowlyincreased after the first steep increase.

Example 10 β-Propiolactone Concentration Effect on Catalyst Activity

To understand how catalyst behaves in high PL content, we studied effectof [PL] on catalyst activity.

A. β-Propiolactone Concentration Effect on Catalyst Activity inSulfolane

PL, which was purchased from Aldrich, dried over 4 Å molecular sieves,and FPT 3 times, was used as a co-solvent to study effect of PLconcentration on catalyst activity in sulfolane (Table 12). The catalystactivity was measured by react-IR.

TABLE 12 [PL]₀ PL initial rate* Exp. # (M) weight % (M/h) 29-128 0 01.97 29-120 1.1 6.6 0.93 29-119 2.2 13.3 0.50 * Conditions: EO:purchased from Arc 1.8M, catalyst: [(ClTPP)Al][Co(CO)₄] 0.36 mmol,solvent: sulfolane (purchased from Aldrich; dried over 4 Å sieves;degassed), agitation 500 rpm, total volume 100 mL; temp 65° C.; COpressure 400 psi * Procedure: EO was added with 400 psi of CO to areaction mixture containing catalyst, sulfolane, and PL at 65° C.*Initial rate: rate of PL formation during the first 5 min

The same reaction procedure as Procedure E was used except for theamount of PL.

The formation of PL during the first 5 min of the EO carbonylation wasplotted as a function of time (FIG. 7), and the PL formation rate wascalculated from the slope of the line. Absorbance of PL was converted toconcentration by using the following equation from linear square fittingof [PL] and IR absorbance.[PL]=2.4367 AU−0.081(AU=Absorbance unit)As shown in Table 15, the catalyst activity is reduced at higher [PL]and is highly dependent on [PL].

Example 11 β-Propiolactone Concentration Effect on Catalyst Activity inTHF

Instead of adding PL before the reaction, PL was converted from EO andaccumulated to a certain level. The second batch of catalyst was addedin the middle of EO carbonylation when [PL] reached at a certain level.The PL formation rate at that point was measured by react-IR. Also, THFwas used as solvent to increase activity and meet the targeted PLformation rate.

One of the reaction profiles from the reactions that were run tocalculate catalyst activity (29-135) is shown in FIG. 8. The reactionwas started by adding EO with 600 psi of CO to a mixture of catalyst andTHF at 65° C. (point A in FIG. 8). The reaction was monitored byreact-IR and when PL content reached 13.8 wt %, 2^(nd) batch of catalyst(0.18 mmol) was added to the reaction mixture with 600 psi of CO (pointB in FIG. 8).

By subtracting the PL formation rate right before point B from the PLformation rate right after point B, the catalyst activity at 13.8 wt %of PL (1.76 M) was obtained. Using the similar experimental procedureand calculation method, the catalyst activity at 24.5 wt % was alsoobtained (Table 16).

TABLE 13 PL formation rate (catalyst 1.8 mM; 65° C.; 600 psi of CO) [PL]PL PL form rate Exp # (M) wt % (M/h) 29-135 0 0 5.21 29-135 1.76 13.83.26 29-137 3.20 24.5 2.17

The absorbance unit from PL peak at 1832 cm⁻¹ was converted toconcentration using the equation shown below. A plot of [PL] versus IRabsorbance unit showed that as [PL] gets close to 3 M, the relationshipbetween IR absorbance and [PL] deviated from the linearity. Therefore, apolynomial best fit was used to obtain the conversion equation.[PL]=0.5075*AU³−0.0573*AU²+2.0525*AU+0.0028(AU=Absorbance unit)

Example 12 Carbonylation of Propylene Oxide

The carbonylation of propylene oxide was studied by varying temperature,CO pressure, and solvent. Propylene oxide was reacted with carbonmonoxide in a 300 mL Parr reactor containing [(ClTPP)Al][Co(CO)₄],hexamethyl benzene (internal standard), and solvent.

TABLE 14 temp pressure PO β- acetone solvent ° C. psi % butyrolactone %dioxane 90 200 21 37 15^(b) dioxane 30 200 60 34 0 dioxane 30 800 46 390 THF 30 200 49 43 0 THF 55 200 0 97 0 THF 30 800 8 91 0 * conditions:[propylene oxide] = 90 mmol (1.8M), [(ClTPP)Al][Co(CO)₄] = 0.06 mmol(1.2 mM), 3 h * no succinic anhydride was observed in these reactions.^(a) yields are based on ¹H NMR integration of PO, β-butyrolactone,acetone and internal standard (hexamethylbenzene) ^(b)the reactionmixture was not pre-saturated with CO before adding PO

As shown in the table above, the higher yields of β-butyrolactone wereattained in THF compared to those in 1,4-dioxane, and the highest yieldwas obtained from the reaction in THF at 55° C. under 200 psi of CO.

Two reactions in 1,4-dioxane under 200 psi CO pressure at 90° C. and 30°C. were monitored every hour for three hours by sampling the reactionmixture. As shown in FIGS. 9 and 10, the percentage of propiolactone inthe reaction mixture at 90° C. does not increase after lh while that inthe reaction mixture at 30° C. steadily increases over time, whichsuggests that the catalyst is deactivated at 90° C. during the firsthour of the reaction.

Representative Reaction Procedure for Carbonylation of Propylene Oxide

A 300 mL Parr reactor was dried overnight under vacuum. In a nitrogenglovebox, the reactor was charged with [(ClTPP)Al] [Co(CO)₄] (66 mg, 60μmol) and hexamethylbenzene (81 mg, 0.50 mmol), then closed and removedfrom the glovebox. Solvent was added via syringe under N₂. The reactionmixture was saturated with CO by pressurizing the reactor with CO to ˜15psi. Propylene oxide (6.3 mL, 90 mmol) was added to the reactor viasyringe. The reactor was pressurized with CO to three fourth of thedesired CO pressure (e.g. 150 psi), then heated to the desiredtemperature. After the temperature of reaction mixture reached thedesired temperature, the reactor was pressurized to the desired pressure(e.g. 200 psi). The reaction mixture was agitated for 3 h. The reactorwas cooled to <0° C. and vented. A portion of reaction mixture wassampled and analyzed by ¹H NMR in CDCl₃.

Example 13 High Boiling Solvent—Solvent Screening

Solvents were selected for the screening process based predominatelyupon boiling point. For efficient separation from propiolactone(b.p.=160° C.), a 30 degree boiling point difference was sought. Theinitial screening included dibasic ester (DBE), N-methylpyrrolidinone(NMP), triglyme, propylene carbonate, and sulfolane. Propylene oxide wasused as a model for ethylene oxide, due to ease of use.

Solvent parameters such as dielectric constant, dipole moment, donornumber, and CO solubility were collected and compared to thedemonstrated activity (tested in the Endeavor reactor, Table 15).

TABLE 15 High-Boiling Solvent Screening Boiling Donor CO Activi- pointDielectric Dipole number ^(a) solubility ty^(b) Solvent (° C.) constantmoment (kcal/mol) (mM) (TO/h) THF 65-57 7.58 1.6 20 21.61 340^(b) 243^(c)  Acetonitrile 81-82 37.5 3.92 14.1 7.42  0^(b) DME 85 Low 1.3120 33.14 88^(b) 1,4-Dioxane 100-102 2.2 0.4 14.8 34.20 100^(b)  Toluene110 2.4 1.3 ~0 37.78   3.4^(b) DBE 196-225 7.7 0.5-1.2 17.1^(d) 20.2855^(c) DBE-3 215-225 17.1^(d) 25.05 68^(c) NMP 202 33 4.1 27.3 19.22 0^(c) Triglyme 216 7.53 2.2 14 22.53   6.3^(c) Tetraglyme 275 20.41 8^(c) Propylene 240 64.4 4.94 15.1 11.13 24^(c) Carbonate Sulfolane 28543.3 4.8 14.8 8.75 45^(c) Phenyl Ether 259 3.9 1.47 17.76 18^(c) BenzylEther 298 1.65 14.45  6^(c) Phthalan 192 73^(c) Propylene Oxide 34 48.38ND β-Butyrolactone ~160 25.05 ND Tetrahydro- 194-195 ND furfurylaceate(753 mmHg) ^(a) Donor number is a measure of the ability to solvatecations. It is the negative enthalpy value for a 1:1 adduct formationbetween the Lewis base and SbCl₅ in dilute solution in C₂H₄Cl₂.^(b)Reaction conditions: Parr reactor, [PO] = 1.0M, [Cat]:[PO] = 500,40° C., 850 psi CO. ^(c)Reaction conditions: Endeavor, [PO] = 1.8M,[Cat]:[PO] = 500, 40° C., 200 psi CO. ^(d)Reported value is for ethylacetate.Solvent Selection and Optimization

Out of all of the solvents screened for the carbonylation of propyleneoxide, dibasic ester and sulfolane were chosen to pursue furtherstudies. Simple adjustments to reaction temperature and pressure weremade, resulting in improved activity in both cases (Table 21). Thecatalyst shows lower activity in sulfolane in general, however increasesin temperature and CO pressure significantly improve the activity.Additionally, carbonylation in a mixture of THF and sulfolane (entry 5)also shows improved activity. In all cases, carbonylation in sulfolaneis highly selective, with no observable byproducts such asmethylsuccinic anhydride.

TABLE 16 Carbonylation of PO in high boiling solvents.^(a) [PO]:Temperature Pressure Activity Expt Solvent [Cat] (° C.) (psi) (TO/h) 1Sulfolane 500 40 200 45 2 Sulfolane 500 60 200 132 3 Sulfolane 500 60400 195 4 Sulfolane 500 90 400 358 5 Sulfolane/THF 500 40 200 61 6 DBE500 40 200 84 7 DBE 500 60 200 198 8 DBE 500 60 400 279 9 DBE 250 60 400290 ^(a)Reaction conditions: Endeavor reactor, [PO] = 1.8M, 5 mLsolution volume.

Carbonylation rates in DBE are also improved by increasing thetemperature and CO pressure. However, selectivity in DBE is not as highas in sulfolane. Significant amounts of methylsuccinic anhydride areformed, particularly at higher temperatures (FIG. 11). It should benoted that the temperature control in the beginning of this reaction wasdifficult, reaching as high as 77° C. in the first 45 min. It appearsthat lactone and anhydride formation is sequential and not simultaneous.Repetition of this experiment (FIG. 12) with better temperature controlresults in slower overall reaction, including slower anhydrideformation. A small amount of anhydride was formed when an additionalinjection of propylene oxide is performed. At this point lactoneformation appears to proceed at the same rate, while the anhydrideconcentration remains constant, lending further support to the theorythat anhydride is only formed after the vast majority of epoxide isconsumed. This behavior indicates that with the right conditions it willbe possible to synthesize the lactone in high yields in DBE with minimalaccumulation of the anhydride.

Example 14 Catalyst Longevity

Preliminary Screening

In order to analyze the length of time the catalyst could maintainactivity, a simple experiment with very low catalyst loadings([PO]:[cat]=10,000) was performed (Table 23, entry 1). The reactionreached completion within 25 h, and samples late in the reaction suggesta linear rate of conversion with time (FIG. 13). Carbonylation of POunder higher catalyst loadings typically give turnover frequencies(TOFs) around 500 TO/h, and even with the low catalyst loadings a TOF of400 TO/h was obtained.

TABLE 17 Carbonylation of PO in THF at low catalyst loadings^(a) [PO]:CO pressure Time TON % Entry [cat] (psi) (h) (mol BBL/mol cat) yield 110,000 200 25 10,000 100 2 20,000 400 27 4370 21.9 3 35,000 200 9415,500 44.3 4 35,000 200 50.5 6,780 19.4 ^(a)Reaction conditions: Parrreactor, [PO] = 1.8M, 55° C., THF.

A significant deviation from linear conversion is noted at[PO]:[cat]=20,000-35,000. Possible causes for this deviation include,impurities in the solvent or substrate which may be more influentialwith respect to the reaction outcome at low catalyst loadings. It isalso possible that the product lactone could inhibit the carbonylationreaction by competing with the epoxide for access to the catalyst. Andfinally, CO solubility is much lower in the lactone than in the epoxide,so as the reaction progresses, the concentration of CO could diminish.

Sequential Monomer Addition

To evaluate cyclical and/or continuous processes an experiment with aseries of monomer additions was performed. The reaction was allowed toproceed to completion (3 hours), at which point another aliquot ofsubstrate was added (FIG. 14). This again proceeded to completionovernight, at which point yet another sample of substrate was added.This third sample only reached about 50% conversion. The reasons forthis loss of activity may be similar to those listed above: impuritiesaccumulated through successive additions of monomer, competitive productinhibition, and changing concentrations of catalyst and CO.

Example 15 Catalyst Thermal Stability

Thermo-Gravimetric Analysis (“TGA”) experiments

In order to evaluate the stability of the catalyst to potentialdistillation conditions, we first set out to study the thermaldecomposition of the catalyst by itself. TGA was used to study thedecomposition of the [(ClTPP)Al][Co(CO)₄], and a decomposition resultingin ˜24% mass loss starts at around 150° C. and is complete by around210° C.

Decomposition Studies

This thermal decomposition behavior was verified by heating the materialin a Schlenk tube at 200° C. for 2 days. Elemental analysis of thisdecomposed compound showed lower carbon and hydrogen content, and highernitrogen and aluminum content than either the initial compound or thetheoretically calculated values (Table 24). The ¹H NMR spectrum shows amixture of peaks corresponding to the known catalyst and new peaks. Inaddition, the material that was heated exhibited a 98% loss in catalyticactivity.

TABLE 18 Carbonylation of PO in THF with thermally decomposed catalyst.C H N Al Catalyst Purification (wt %) (wt %) (wt %) (wt %) TOF ^(a)37-019 Precipitation 57.21 3.95 4.82 2.40 254 Theoretical 61.56 3.695.13 2.47 26-286 Heat at 200° C. 51.33 3.38 5.65 2.71 4.7 ^(a) Reactionconditions: Endeavor reactor, [PO] = 1.8M, [PO]:[cat] = 500, 40° C., 400psi, THF.

Preliminary Heat Cycles

Carrying the thermal decomposition study further, we prepared a catalystsolution in the given solvent and preheated the solution to 90° C. (aconvenient temperature for vacuum distillation). The solution was thencooled, propylene oxide was added, and carbonylation carried out asusual. In the case of both THF and sulfolane, activity was comparableafter a preheat period to the non-heated reaction.

TABLE 19 Carbonylation of PO with a preheat cycle. TON Preheat PreheatCO (mol [PO]: time temp Rxn temp pressure Time BBL/ % Entry Solvent[cat] (min) (° C.) (° C.) (psi) (h) mol cat) yield 1 THF 1500 0 NA 55200 3 1489 99 2 THF 1500 60 90 55 200 3 1460 97 3 Sulfolane 500 0 NA 60400 3 500 99 4 Sulfolane 500 30 90 60 400 3 500 99 ^(a) Reactionconditions: Parr reactor, [PO] = 1.8M. For preheat cycles, the catalystand solvent were heated under N₂.

Recycle

An apparatus for the distillation of lactone product directly from theParr reactor was constructed.

Even though there is more than a 30° C. boiling point differentialbetween the lactone and the dibasic ester solvent, this simple apparatusdid not give a clean distillation. In fact more than half of the solventin the reactor distilled with the lactone product. For this reason,sulfolane (bp=296° C.) was chosen as the solvent for the initialcatalyst recycling studies (Table 26). The carbonylation conditions wereheld constant, at 60 C and 400 psi CO, while the distillationtemperature following the reaction was steadily increased after eachcycle. Catalyst activity appears to be maintained after distillations at90 and 100° C., but suffers markedly after distillation at 110° C.

TABLE 20 Carbonylation of PO in sulfolane with recycles.^(a) TimeTurnovers Distill time Distill temp Yield Cycle (h) (mol BBL/mol cat)(min) (° C.) (g) 1 1 90 30 90 5 2 1 173 30 100 15 3 1 102 30 110 7 4 1534 30 100 1 ^(a)Reaction conditions: Parr reactor, [PO] = 1.8M, [PO]:[cat] = 250, 60° C., 400 psi, sulfolane.

A second recycle experiment in sulfolane with sampling during thereaction is shown below in FIG. 15. Activity appears to be somewhat lessduring the second cycle, following distillation at 90 C for 35 minutes,and complete conversion was not attained. However, analysis of sulfolanesolutions by NMR is greatly complicated due to the fact that our typicalinternal standards are insoluble in sulfolane, and the sulfolane peakscoincide with the byproduct peaks we expect.

Example 16 NMR Spectroscopy

NMR spectroscopy has been a standard method of analysis for some time(FIG. 16). For the most part, however, the only useful information whichcomes from this spectrum is the amount of THF in the catalyst. Two THFmolecules are bound to the Al center, and additional molecules(typically 0.2 to 1.0) may result from incomplete drying.

Example 17 Infrared Spectroscopy

The Co(CO)₄ component of the catalyst has a strong absorbance at 1888cm⁻¹. The NaCo(CO)4 starting material has a peak which is shifted fromthis. FIG. 17 shows an overlay of the catalyst product and the twostarting materials. A peak at ˜465 cm⁻¹ is expected for the Al—Cl bondin the (Cl-TPP)AlCl starting material, however data below 600 cm⁻¹ iscut off.

Example 18 Catalyst Stability

Design of a continuous process for the carbonylation of ethylene oxideto form propiolactone requires a catalyst which maintains activity for asignificant amount of time. There are a number of factors which mayinfluence the long-term stability of the catalyst, includingtemperature, solvent, impurities, and material compatibility.

Carbonylation: The carbonylation reaction is shown in Scheme 8 below.Coordination of an epoxide to the Lewis acid Al⁺ center, followed bynucleophilic attack on the epoxide by the [Co(CO)₄]⁻ anion leads to ringopening of the epoxide (2). CO insertion is typically swift to form theCo-acyl 3, which is the resting state of the catalyst in THF. Ringclosing of the lactone is the rate determining step in THF, followed byloss of the lactone and coordination of another solvent molecule toreform the ion pair 1. At high temperatures and low CO concentrations,however, 2 can undergo β-hydrogen elimination to form a ketone molecule,which is a fast and exothermic reaction. In certain solvents, thelactone can undergo subsequent carbonylation to an anhydride molecule.This typically occurs at high temperatures and when the concentration ofepoxide becomes very low. The formation of anhydride is also solventdependent, being very fast in DBE, and almost non-existent in THF andsulfolane.

Catalyst thermal stability In order to assess the catalyst's thermalstability, the catalyst was heated under N₂ in a Schlenk tube and theresulting material was tested for PO carbonylation activity in theEndeavor reactor (Table 29) in order to determine the importance of bothtemperature and time on the catalyst activity. Under the conditions ofthe study most of the catalyst residues maintained their activities(entries 2-5, in table 29). Only the catalysts exposed to hightemperatures for long times (entries 6 and 7) resulted in a materialwith low activity. It appears that the catalyst can withstand hightemperatures so long as it is for less than 5 hours. ¹H NMR spectroscopyof the material from entry 6 showed broad aromatic peaks and whatappears to be a formula of [(ClTPP)Al][Co(CO)₄](THF), where the startingcatalyst (entry 1) has a formula of [(ClTPP)Al][Co(CO)₄](THF)₂.₅ by NMR.The material produced in entry 7 unfortunately was insoluble so NMRanalysis was impossible.

TABLE 21 Carbonylation of PO with catalyst that have been preheated.^(a)Preheat temp Preheat time BBL PO TOF Entry (° C.) (h) equiv equiv (h⁻¹)1 NA NA 506 22 253 2 100 1.25 495 0 248 3 100 5 484 33 242 4 140 3.88528 2 264 5 180 1.38 474 15 237 6 180 5 285 131 143  7^(b) 200 48 14 4394.7 ^(a)Catalyst heated under N₂ for given time at given temperature. POcarbonylation conditions: Endeavor reactor, [PO] = 1.8M, [PO]: [cat] =500, THF 40° C., 200 psi, 2 h. ^(b)Reaction time = 3 h.

Example 19 React-IR Monitoring

Representative spectra in the carbonylation of propylene oxide andethylene oxide are shown in FIGS. 18 and 19, respectively. Formation ofthe product lactone can be monitored (1827 cm⁻¹ for BBL and 1836 cm⁻¹for PL), as well as the formation of the ketone and anhydridebyproducts. It is also possible to track the catalyst form, with a peakat 1887 cm-1 corresponding the catalyst 1, and a peak at 1715 cm⁻¹corresponding to the Co acyl 3. In DBE the peak for 1 disappears rapidly(<15 seconds) upon the addition of epoxide, and the appearance of 3 isdifficult to observe, as it coincides with peaks for the ketone as wellas the ester groups in DBE. In sulfolane, no peak at 1887 cm⁻¹ isobservable, however a number of other peaks in the 1570-1700 cm⁻¹ regionhave been noted but have yet to be identified.

Example 20 Solvent Stability

Catalyst stability in DBE-3 was evaluated by monitoring the IR spectrumof the solution under N₂ for 18 h. The peak at 1887 cm⁻¹ correspondingto the [Co(CO)₄]⁻ remained constant during that time period. PO and COwere added to the catalyst solution, and carbonylation went tocompletion in 2.5 h. At the end of the cycle, the [Co(CO)₄]⁻ peakreturned at 79% of its original value (concentration corrections due tothe addition of PO have been accounted for). However during thedistillation this peak appeared to decay, and a subsequent addition ofPO resulted in poor carbonylation activity.

Example 21 Pressure Effects

In a previous DOE set of experiments of the carbonylation of EO in DBE,a pressure effect has not been observed, and so for the most part we hadused 400 psi and largely ignored any potential pressure effect. At leastin sulfolane, however, we determined that while initial rates weresimilar, over time the reaction at 600 psi performed much better thanthe one at 400 psi (FIG. 20).

Example 22 Temperature

A comparison of reaction temperatures was performed to help determinethe optimal conditions for the catalyst test unit. The results of thistest are shown below in FIG. 21. At 50° C. and 65° C., the reaction wasperformed with duplicate injections of EO (both 1.8 M). The rates at 65°C. are more than double the rates at 50° C. FIG. 21 illustrate thecomparison of conditions and resulting reaction rates.

We claim:
 1. A continuous method of making poly(3-hydroxy propionicacid) from ethylene oxide, the method comprising steps of: reacting thecontents of a feed stream comprising ethylene oxide, a solvent, acarbonylation catalyst and carbon monoxide to produce a liquid reactionproduct stream comprising beta-propiolactone and a carbonylationcatalyst; separating at least a portion of the beta-propiolactone in thereaction product stream from the carbonylation catalyst to produce aliquid catalyst recycling stream comprising carbonylation catalyst;polymerizing at least a portion of the separated beta-propiolactone toproduce poly(3-hydroxy propionic acid); and adding the liquid catalystrecycling stream to the feed stream.
 2. A continuous method of makingpoly(3-hydroxy propionic acid) from ethylene oxide, the methodcomprising steps of: reacting the contents of a feed stream comprisingethylene oxide, a solvent, a carbonylation catalyst and carbon monoxideto produce a liquid reaction product stream comprisingbeta-propiolactone and a carbonylation catalyst; returning the liquidreaction product stream to the feed stream until the weight percent ofbeta-propiolactone in the liquid reaction product stream is in the rangeof about 10% to about 90%; and then separating at least a portion of thebeta-propiolactone in the reaction product stream from the carbonylationcatalyst to produce a liquid catalyst recycling stream comprisingcarbonylation catalyst; polymerizing at least a portion of the separatedbeta-propiolactone to produce poly(3-hydroxy propionic acid); and addingthe liquid catalyst recycling stream to the feed stream.
 3. The methodof claim 1, further comprising treating the poly(3-hydroxy propionicacid) under conditions to convert the poly(3-hydroxy propionic acid)into a compound selected from the group consisting of acrylic acid,acrylates, acrylamide, and polyacrylates.
 4. The method of claim 1,further comprising treating the poly(3-hydroxy propionic acid) underconditions to convert the poly(3-hydroxy propionic acid) into a compoundselected from the group consisting of acrylic acid, methyl acrylate,ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and 2-ethylhexylacrylate.
 5. The method of claim 1, further comprising treating thepoly(3-hydroxy propionic acid) under conditions to convert thepoly(3-hydroxy propionic acid) into acrylic acid.
 6. The method of claim1, wherein, upon reacting, the solvent has a boiling point that ishigher than the boiling point of the beta-propiolactone when the solventand beta-propiolactone are at the same pressure.
 7. The method of claim1, wherein the liquid catalyst recycling stream comprisesbeta-propiolactone.
 8. The method of claim 1, wherein the liquidreaction product stream comprises ethylene oxide.
 9. The method of claim8, wherein the liquid reaction product stream comprises an amount ofethylene oxide sufficient to prevent anhydride formation.
 10. The methodof claim 9, wherein the liquid reaction product stream comprises atleast about 0.1% ethylene oxide by weight.
 11. The method of claim 1,further comprising treating the liquid catalyst recycling stream, priorto the adding step, by adding fresh carbonylation catalyst, removingspent carbonylation catalyst, adding solvent, adding ethylene oxide,adding a portion of the separated beta-propiolactone, or a combinationthereof.
 12. The method of claim 1, wherein the separating stepcomprises volatilizing at least a portion of the beta-propiolactone fromthe liquid reaction product stream to produce the separatedbeta-propiolactone.
 13. The method of claim 1, wherein the separatingstep comprises exposing the liquid reaction product stream to reducedpressure.
 14. The method of claim 13, wherein the reduced pressure isbetween about 5Torr and about 500 Torr.
 15. The method of claim 13,wherein the reduced pressure is between about 10Torr and about 100 Torr.16. The method of claim 13, wherein the reduced pressure is sufficientto reduce the boiling point of the beta-propiolactone by about 20 toabout 100 ° C. below its boiling point at atmospheric pressure.
 17. Themethod of claim 1, wherein the separating step comprises exposing theliquid reaction product stream to elevated temperature.
 18. The methodof claim 17, wherein the elevated temperature is greater than theboiling point of the beta-propiolactone but less than the boiling pointof the solvent.
 19. The method of claim 1, wherein the separating stepcomprises exposing the liquid reaction product stream to reducedpressure and elevated temperature.
 20. The method of claim 12, furthercomprising a step of condensing beta-propiolactone from the separatedbeta-propiolactone.
 21. The method of claim 1, further comprising addingbeta-propiolactone to the feed stream.
 22. The method of claim 21,wherein the beta-propiolactone added to the feed stream is taken fromthe separated beta-propiolactone.
 23. The method of claim 22, whereinthe beta-propiolactone is added to the feed stream until the weightpercent of beta-propiolactone in the liquid reaction product stream isin the range of about 10% to about 90%, and the method then compriseswithdrawing beta-propiolactone from the liquid reaction product streamwhile maintaining the weight percent of beta-propiolactone in the liquidreaction product stream in the range of about 10% to about 90%.
 24. Themethod of claim 1, wherein the boiling point of the solvent is at least20° C. higher than the boiling point of the beta-propiolactone.
 25. Themethod of claim 1, wherein the solvent has a boiling point of at least172° C. at atmospheric pressure.
 26. The method of claim 1, wherein thecarbonylation catalyst comprises a metal carbonyl compound.
 27. Themethod of claim 26, wherein the metal carbonyl compound has the generalformula [QM_(y)(CO)_(w)]^(x), where: Q is any ligand and need not bepresent; M is a metal atom; y is an integer from 1 to 6 inclusive; w isa number that provides a metal carbonyl compound that is stable; and xis an integer from −3 to +3 inclusive.
 28. The method of claim 27,wherein M is selected from the group consisting of Ti, Cr, Mn, Fe, Ru,Co, Rh, Ni, Pd, Cu, Zn, Al, Ga and In.
 29. The method of claim 27,wherein M is Co.
 30. The method of claim 27, wherein M is Co, y is 1,and w is
 4. 31. The method of claim 27, wherein the metal carbonylcompound comprises a carbonyl cobaltate and the carbonylation catalystfurther comprises a Lewis acidic co-catalyst which comprises ametal-centered cationic Lewis acid.
 32. The method of claim 31, whereinthe metal-centered cationic Lewis acid comprises an aluminum cation. 33.The method of claim 1, wherein the liquid reaction product streamcomprises carbon monoxide and ethylene oxide and the separating stepcomprises: separating the liquid reaction product stream into i) agaseous stream comprising carbon monoxide and ethylene oxide, and ii) aliquid stream comprising beta-propiolactone and carbonylation catalyst;and separating the liquid stream comprising beta-propiolactone andcarbonylation catalyst into i) the separated beta-propiolactone; and ii)the liquid catalyst recycling stream comprising carbonylation catalyst.34. The method of claim 33, wherein the solvent has a boiling pointhigher than the boiling point of the beta-propiolactone and the catalystrecycling stream further comprises solvent.
 35. The method of claim 33,further comprising the step of returning the gaseous stream comprisingcarbon monoxide and ethylene oxide to the feed stream.
 36. The method ofclaim 33, wherein the solvent has a boiling point lower than the boilingpoint of the beta-propiolactone and the gaseous stream comprising carbonmonoxide and ethylene oxide further comprises solvent.
 37. The method ofclaim 2, wherein the liquid reaction product stream is returned to thefeed stream until the weight percent of beta-propiolactone in the liquidreaction product stream is in the range of about 43% to about 53%, andthe method then comprises withdrawing beta-propiolactone from the liquidreaction product stream while maintaining the weight percent ofbeta-propiolactone in the liquid reaction product stream in the range ofabout 43% to about 53%.
 38. The method of claim 1, wherein the separatedbeta-propiolactone is gaseous.
 39. The method of claim 2, wherein theseparated beta-propiolactone is gaseous.